Journals >Semiconductor Optoelectronics
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2022
Volume: 43 Issue 3
30 Article(s)
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Research Progress of GaNbased Highspeed Blue and Green Light Source
LI Zhenhao, WANG Lai, HAO Zhibiao, LUO Yi, SUN Changzheng, HAN Yanjun, XIONG Bing, WANG Jian, and LI Hongtao
With the gradual saturation of the spectrum resources of radio frequency communication, there is an urgent need to open up a new race track for local highspeed communication, while visible light communication benefits from the nature of large bandwidth and spectrum licensefree since limited communication range, whichWith the gradual saturation of the spectrum resources of radio frequency communication, there is an urgent need to open up a new race track for local highspeed communication, while visible light communication benefits from the nature of large bandwidth and spectrum licensefree since limited communication range, which is one of the ideal supplements of traditional communication. The rapid development of GaNbased bluegreen light source in the past decade, especially the development of microLED as the small size and high speed light source with excellent performance, has made it an important driving force for terminal communication in the "Internet of Everything" era of Internet of Things. In this paper, the development history and recent progress of bluegreen highspeed light sources are reviewed from two main categories: bluegreen microLED and GaNbased bluegreen light sources with resonators (including superluminescent diodes and lasers). It mainly includes three aspects: microLED structure and array, surface emitting cavity enhanced light source and edge emitting cavity enhanced light source..
Semiconductor Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 3, 405 (2022)
Progress of AlGaN Photodetectors and Focal Plane Array Technologies
WANG Ying, and WANG Zhen
AlGaN UV photodetectors and focal plane arrays, as allsolidstate devices, have intrinsic visible blind characteristics and can achieve solarblind detection without filters, thus they have become an important development trend for UV detection technology. In this paper, the developments and existing problems of AlGaNAlGaN UV photodetectors and focal plane arrays, as allsolidstate devices, have intrinsic visible blind characteristics and can achieve solarblind detection without filters, thus they have become an important development trend for UV detection technology. In this paper, the developments and existing problems of AlGaN UV photodetectors and focal plane arrays are introduced. The development status and trends of AlGaN APD are also discussed..
Semiconductor Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 3, 430 (2022)
Preparation of βGa2O3 Nanodot Array Films on GaAs Substrates by MetalOrganic Chemical Vapor Deposition
CHEN Wei, JIAO Teng, LI Zeming, DIAO Zhaoti, LI Zhengda, DANG Xinming, CHEN Peiran, and DONG Xin
βGa2O3 nanodot array films on intrinsic GaAs substrates have been presented by combining thermal oxidation and MOCVD technology, which does not involve metal catalysts or complex etching. Morphological features of the prepared films were characterized and analyzed by scanning electron microscope (SEM). It is found thaβGa2O3 nanodot array films on intrinsic GaAs substrates have been presented by combining thermal oxidation and MOCVD technology, which does not involve metal catalysts or complex etching. Morphological features of the prepared films were characterized and analyzed by scanning electron microscope (SEM). It is found that the βGa2O3 nanodot array films show a pentagonal columnar structure. Xray diffraction, Raman vibration, and photoluminescence were performed on the prepared samples, and the results show that the crystal quality of the films is optimized with the increase of MOCVD growth temperature and Ⅵ/Ⅲ ratio. The finite element method (FEM) simulations verify that the βGa2O3 nanodot array films are highly light trapping. The nanodot array films prepared by this process show high specific surface area with high light trapping..
Semiconductor Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 3, 438 (2022)
Multifunctional MicroLED Array Monolithic Integration with Luminescence and Photodetection for Display and Visible Light Communication
SHAN Xinyi, ZHU Shijie, WANG Zhou, LIN Runze, CUI Xugao, FANG Zhilai, GU Erdan, and TIAN Pengfei
GaNbased microLED, as a burgeoning light source technology, has been demonstrated to play an important role in optical communication and display fields, etc. If the pixels in microLED array can detect the optical performance of the adjacent pixels, it is expected to realize multifunctional microLED array for monoliGaNbased microLED, as a burgeoning light source technology, has been demonstrated to play an important role in optical communication and display fields, etc. If the pixels in microLED array can detect the optical performance of the adjacent pixels, it is expected to realize multifunctional microLED array for monolithic integration with light detection, thus promoting the development of photonic integrated chips for Internet of Things technology toward miniaturization and low power consumption. It was experimentally verified that InGaN/GaN MQWs can realize the dual functions of luminescence and detection under different operating voltages, thus proving the feasibility of microLED array monolithic integrated luminescence and realtime detection. Moreover, microLED array was further applied in high stability visible light communication and realtime detection of dead pixels in display array, which broadens the potential applications of microLED array..
Semiconductor Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 3, 444 (2022)
Current Status and Advances of GaNbased UV Laser Diodes for NearUV Wavelength
LI Yaqin, LIU Jianpin, TIAN Aiqin, LI Fangzhi, HU Lei, LI Deyao, and YANG Hui
GaNbased UV laser diodes for nearUV wavelength (UVA LD, 320~400nm) are widely applied in the fields such as UV curing, 3D printing and medical. In this paper, the current status and key technical challenges of GaNbased UVA LD are reviewed, and then how to solve the main challenges of stress management, efficient ptGaNbased UV laser diodes for nearUV wavelength (UVA LD, 320~400nm) are widely applied in the fields such as UV curing, 3D printing and medical. In this paper, the current status and key technical challenges of GaNbased UVA LD are reviewed, and then how to solve the main challenges of stress management, efficient ptype doping in AlGaN and minimizing polarization effect in multiquantum wells are analyzed from the epitaxial growth and structural design. This will provide theoretical guidance for the epitaxial growth of the GaNbased UVA LD with high power, low threshold and long life..
Semiconductor Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 3, 451 (2022)
Growth and Characterization of Nonpolar aplane nAlGaN Epitaxial Layer
FANG Ruiting, CHEN Shuai, ZHANG Xiong, and CUI Yiping
The Sidoped nonpolar aplane nAlGaN epitaxial layer with high electron concentration and good surface morphology was successfully grown on semipolar sapphire substrate by metal organic chemical vapor deposition. The effects of indium (In) surfactant and undoped AlGaN buffer layer on the structural and electrical propThe Sidoped nonpolar aplane nAlGaN epitaxial layer with high electron concentration and good surface morphology was successfully grown on semipolar sapphire substrate by metal organic chemical vapor deposition. The effects of indium (In) surfactant and undoped AlGaN buffer layer on the structural and electrical properties of the nAlGaN epitaxial layer were intensively studied. The characterization results show that the anisotropy in crystalline quality of the nonpolar aplane nAlGaN epitaxial layer is effectively suppressed by using In surfactant and undoped AlGaN buffer layer, and its surface morphology and electrical properties are significantly improved. In fact, the electron concentration and electron mobility are determined to be -4.8×1017cm-3 and 3.42cm2/(V·s), respectively..
Semiconductor Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 3, 461 (2022)
Design of Novel Vertical GaNBased Trench Gate MOSFET with Electric Field Shielding Function of Gate Dielectric
LI Chenglang, WU Qianshu, ZHOU Yuhao, ZHANG Jinwei, LIU Zhenxing, ZHANG Qi, and LIU Yang
Metaloxidesemiconductor field effect transistor (MOSFET) devices based on wide bandgap (WBG) semiconductors such as gallium nitride (GaN) have a high electric field equivalent to the critical breakdown electric field of WBG semiconductor in the gate dielectric under the offstate voltage, which dampens the longterm Metaloxidesemiconductor field effect transistor (MOSFET) devices based on wide bandgap (WBG) semiconductors such as gallium nitride (GaN) have a high electric field equivalent to the critical breakdown electric field of WBG semiconductor in the gate dielectric under the offstate voltage, which dampens the longterm reliability of the gate dielectric. In order to avoid using the immature ptype ion implantation technology in GaN devices, a new type of vertical GaNbased trench gate MOSFET based on selective area epitaxy is proposed, which can improve the gate dielectric reliability by reducing the offstate gate dielectric electric field. And a process preparation based on selective region epitaxy is designed to avoid the etching damage of MOS interface. The space charge competition model of the depletion region junction capacitance in the offstate is proposed, and the influence law and mechanism of the structural parameters of ptype shielding structure on the gate dielectric electric field are qualitatively explained. By trade off the relationship between device performance and reliability, a novel vertical GaNbased trench gate MOSFET with longterm reliability of gate dielectric is obtained with the breakdown voltage of 1200V and gate dielectric electric field of 0.8MV/cm..
Semiconductor Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 3, 466 (2022)
Recent Progresses on Structure and Properties of Twodimensional Diamond
GAO Nan, LIU Yaning, and LI Hongdong
Twodimensional diamond (2DD) is an atomically thick diamond film having unique characteristics with retaining intrinsic properties of bulk diamonds. Currently, researches on 2DD mainly focus on theoretical investigations of structure, functionalization, and electrical properties, while a few of experimental works arTwodimensional diamond (2DD) is an atomically thick diamond film having unique characteristics with retaining intrinsic properties of bulk diamonds. Currently, researches on 2DD mainly focus on theoretical investigations of structure, functionalization, and electrical properties, while a few of experimental works are reported on preparation. In this paper, the theoretical and experimental progresses of structure, surface functional modulation and electrical properties of 2DD are briefly reviewed dependent on atomic thickness (layer number), and the development trends, challenges, and potential applications are discussed..
Semiconductor Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 3, 472 (2022)
Research Progress of Hexagonal Boron Nitride Neutron Detector
FAN Ziyang, CHEN Xi, CHEN Zhanguo, ZHAO Jiangbin, and HE Gaokui
Hexagonal boron nitride (hBN) neutron detectors present such advantages as small leakage current, small volume, fast response speed, high detection efficiency and insensitivity to γrays, thus they are expected to be widely used as supplements of the traditional 3He gas detector and microstructure semiconductor neutronHexagonal boron nitride (hBN) neutron detectors present such advantages as small leakage current, small volume, fast response speed, high detection efficiency and insensitivity to γrays, thus they are expected to be widely used as supplements of the traditional 3He gas detector and microstructure semiconductor neutron detector. The principles of hBN neutron detector are introduced in this paper, and the research progressed of hBN neutron detector in recent years are also reviewed, including the preparation process of hBN films, the structure and performance of hBN neutron detectors and so on..
Semiconductor Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 3, 479 (2022)
Progress of Radiation Effects on GaInP/GaAs/Ge Triple Junction Solar Cells
WANG Zujun, WANG Xinghong, YAN Shixing, TANG Ning, CUI Xinyu, ZHANG Qi, SHI Mengqi, HUANG Gang, NIE Xu, and LAI Shankun
With the wide applications of GaInP/GaAs/Ge threejunction solar cells used in spacecraft as a space power supply system, the problem of space radiation damage is widely concerned. The performance of GaInP/GaAs/Ge threejunction solar cells will be degraded by the irradiation of the electrons, protons and other radiatiWith the wide applications of GaInP/GaAs/Ge threejunction solar cells used in spacecraft as a space power supply system, the problem of space radiation damage is widely concerned. The performance of GaInP/GaAs/Ge threejunction solar cells will be degraded by the irradiation of the electrons, protons and other radiation particles or rays in the space radiation environment. In this paper, the research progress of the radiation experiments of GaInP/GaAs/Ge triplet solar cells induced by the electrons, protons and other radiation particles or rays at home and abroad is introduced in depth, and then the research progress of the simulation of radiation damage effect, radiation hardening, and radiation damage prediction of GaInP/GaAs/Ge threejunction solar cells is reviewed. The key problems in the research of radiation damage effect on GaInP/GaAs/Ge threejunction solar cells are summarized. It provides theoretical guidance and experimental technical support for the establishment of the experimental method of radiation damage effect, the analysis of damage mechanism, the prediction of inorbit life and the research of radiation hardening technology of GaInP/GaAs/Ge threejunction solar cells..
Semiconductor Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 3, 490 (2022)
Effects of Thickness of Dual ModerateTemperatureGrown AlN Interlayers on Surface Morphology and Crystalline Quality of SemiPolar (1122) AlN Epilayer
CUI Jia, LUO Xuguang, ZHANG Xiong, and CUI Yiping
A series of semipolar (1122) AlN epilayers have been grown on (1010) mplane sapphire substrates with the help of dual moderatetemperaturegrown (MTG) AlN interlayers by metalorganic chemical vapor deposition (MOCVD). Significant improvements in both surface morphology and crystalline quality of the semipolar (1122A series of semipolar (1122) AlN epilayers have been grown on (1010) mplane sapphire substrates with the help of dual moderatetemperaturegrown (MTG) AlN interlayers by metalorganic chemical vapor deposition (MOCVD). Significant improvements in both surface morphology and crystalline quality of the semipolar (1122) AlN epilayers have been achieved with the insertion of the MTGAlN interlayers due to the formation of nanoscale patterned substratelike structure and the reduction in the basalplane stacking faults and their associated partial dislocations. The effect of the variation in the thickness of the MTGAlN interlayer ranged from 20 to 100nm was investigated in detail based on the characterization results of atomic force microscopy (AFM) and Xray diffraction. It was revealed that all the semipolar AlN epilayer samples were uniquely [1122]oriented regardless of the variation in the thickness of the MTG AlN interlayer. It was found that the most remarkable reduction in surface roughness and the most notable improvement in crystalline quality could be obtained when the thickness for the inserted dual MTGAlN interlayers was approximately 80nm..
Semiconductor Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 3, 505 (2022)
Performance and Mechanism Analysis of Thin Absorption Region AlGaN Schottky Solarblind Detector with Different Metal Contact
HU Lefeng, and ZHANG Yan
For a Schottky detector with a thin absorption region of 100~200nm, the influence of different metal contacts on the dark current and spectral response characteristics was studied. Taking GaNbased materials as the main body, Au and Ni/Au were prepared on the surface of thin Al0.42Ga0.58N to form Schottky contacts, andFor a Schottky detector with a thin absorption region of 100~200nm, the influence of different metal contacts on the dark current and spectral response characteristics was studied. Taking GaNbased materials as the main body, Au and Ni/Au were prepared on the surface of thin Al0.42Ga0.58N to form Schottky contacts, and Ti/Al/Ti/Au were prepared on the surface of Al0.55Ga0.45N to form ohmic contacts. Thus, an AlGaN Schottky solarblind detector with a thin absorption region is fabricated. The results show that for AlGaN material, the photoresponse of Au Schottky detector is good, reaching 0.10A/W, the peak external quantum efficiency is 47%, but the dark current is slightly larger, which is 3.91×10-10A/cm2. The dark current of Ni/Au Schottky detector is stable at 4.17×10-11A/cm2, while the responsivity is generally 0.07A/W, and the external quantum efficiency is 33%. The test results are consistent with the simulation model. For the front irradiation mode, Au Schottky detector has a larger response range and higher responsivity than Ni/Au Schottky detector due to factors such as barrier height and interface loss layer. For the back irradiation mode, the thickness of the absorption layer has a great effect on the response range, and the thin absorption region effectively extends the response range..
Semiconductor Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 3, 510 (2022)
Effect of ScAlN Buffer Layer Thickness on GaN Epitaxial Layer on Si(100) Substrate
YIN Haotian, DING Guangyu, HAN Jun, XING Yanhui, and DENG Xuguang
ScAlN thin films were first prepared on Si (100) substrate by pulsed DC magnetron sputtering. Then, GaN thin films were epitaxial grown on Si (100) substrate with metalorganic chemical vapor deposition (MOCVD) by using ScAlN as the buffer layer. The influence of the thickness of ScAlN buffer layer on ScAlN buffer layeScAlN thin films were first prepared on Si (100) substrate by pulsed DC magnetron sputtering. Then, GaN thin films were epitaxial grown on Si (100) substrate with metalorganic chemical vapor deposition (MOCVD) by using ScAlN as the buffer layer. The influence of the thickness of ScAlN buffer layer on ScAlN buffer layer and GaN epitaxial layer is investigated by high resolution Xray diffraction, atomic force microscopy (AFM) and Raman spectroscopy. The results show that the thickness of ScAlN buffer layer is an important factor affecting the crystal quality of GaN thin films. With the increase of ScAlN thickness, the full width at half maximum (FWHM) of ScAlN (002) Xray diffraction rocking curve continues to decrease, and the FWHM of GaN (002) Xray diffraction rocking curve first decreases and then increases. When the thickness of ScAlN buffer layer is 500nm, the crystal quality of GaN is the best, the FWHM of GaN (002) Xray diffraction rocking curve is 0.38°, and the tensile stress calculated by Raman spectrum is 398.38MPa..
Semiconductor Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 3, 517 (2022)
Investigation of External Quantum Efficiency of GaNbased MicroLEDs
YANG Hang, HUANG Wenjun, ZHANGHU Mengyuan, LIN Yonghong, and LIU Zhaojun
GaNbased microsized lightemitting diodes (microLED) has gradually become the main light source in many optoelectronic devices such as visible light communications and nextgeneration displays. Low external quantum efficiency (EQE)，caused by nonradiative recombination and quantum confined Stark effect (QCSE)，is theGaNbased microsized lightemitting diodes (microLED) has gradually become the main light source in many optoelectronic devices such as visible light communications and nextgeneration displays. Low external quantum efficiency (EQE)，caused by nonradiative recombination and quantum confined Stark effect (QCSE)，is the main bottleneck in applications of microLEDs. In this report, the reasons for low EQE of microLEDs are discussed, and the physical characteristics of microLEDs are analyzed and several optimal methods are suggested to improve EQE..
Semiconductor Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 3, 522 (2022)
Research Progresses of Ultraviolet LightEmitting Diodes (UV LEDs) Disinfection Technology in Water Microbial Inactivation
YANG Chengshuang, WANG Xinchang, SUN Guanlang, FAN Bingfeng, and XIE Jianing
In this article, first, the technical bottlenecks of ultraviolet lightemitting diodes (UV LEDs) encountered in the current stage of research and development are introduced. Then the inactivation mechanism of UV LEDs to harmful microorganisms in water is analyzed. In the process of microbial inactivation, the differentIn this article, first, the technical bottlenecks of ultraviolet lightemitting diodes (UV LEDs) encountered in the current stage of research and development are introduced. Then the inactivation mechanism of UV LEDs to harmful microorganisms in water is analyzed. In the process of microbial inactivation, the different application types of UV LEDs are examined in detail, including the application of UV LEDs in different types of UV reactors, advanced oxidation processes (AOPs) based on UV LEDs, the combined use of UV LEDs with different wavelengths, etc. Finally, the issues of deep UV LEDs in the field of drinking water sterilization and disinfection are summarized and an outlook is put forward..
Semiconductor Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 3, 529 (2022)
Progress on Performance Modification of Bismuthbased Leadfree Piezoelectric Sensitive Materials
YANG Fengjuan, ZHONG Haiying, CHEN Yanbin, and WANG Yi
Highperformance electronic devices with leadfree piezoelectric materials have been widely applied in various fields. Bismuthbased materials have certain comprehensive properties, especially in the field of high temperature piezoelectric, which is a candidate system with potential to replace PZTbased materials. In tHighperformance electronic devices with leadfree piezoelectric materials have been widely applied in various fields. Bismuthbased materials have certain comprehensive properties, especially in the field of high temperature piezoelectric, which is a candidate system with potential to replace PZTbased materials. In this paper, an overview of the research advances related to the key problem of how to modified the properties of leadfree piezoelectric materials is provided, focusing on the following aspects, such as the control of material components to modify the multiphase boundary, doping, adjustment of preparation process and domain engineering. In addition, this perspective tries to analyze the problems that still need to be solved in the practical applications of leadfree piezoelectric materials..
Semiconductor Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 3, 539 (2022)
Design and Fabrication of Four Spectral TDICCD Image Sensor
XU Daorun, LIU Yeqi, YUAN Anbo, LIAO Naiman, QU Pengcheng, LUO Chunlin, and ZHANG Xiaoqin
A kind of four spectral timedelayintegrated charge coupled device (TDI CCD) is designed and fabricated by integrating four TDICCDs on one chip. Different narrowband filter films are plated on the corresponding positions of the light window to realize multiband light splitting. For the designed TDICCD, its pixel sizA kind of four spectral timedelayintegrated charge coupled device (TDI CCD) is designed and fabricated by integrating four TDICCDs on one chip. Different narrowband filter films are plated on the corresponding positions of the light window to realize multiband light splitting. For the designed TDICCD, its pixel size is 28μm×28μm, the horizontal pixel size is 3072 elements, the line frequency is 10kHz, the charge transfer efficiency is 0.99999, the saturation output voltage is 2650mV, the antiblooming ability is more than 100×, and the dynamic range is 7143∶1..
Semiconductor Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 3, 547 (2022)
Analysis of Instability Factors of Selfinjection Locking of DFB Semiconductor Laser
HU Kangyong, SONG Weining, ZHU Xuyang, and KONG Mei
Distributed feedback (DFB) semiconductor lasers have the advantages of small size, low cost and mature manufacturing technology. However, their application scope is limited due to the MHz linewidth. The linewidth can be narrowed to the order of kHz by selfinjection locking with ring resonators, but there exists instabDistributed feedback (DFB) semiconductor lasers have the advantages of small size, low cost and mature manufacturing technology. However, their application scope is limited due to the MHz linewidth. The linewidth can be narrowed to the order of kHz by selfinjection locking with ring resonators, but there exists instability as the laser being locked. We selfinjection lock a DFB semiconductor laser to four different ring resonators and monitor the changes of optical power, polarization state and wavelength at multiple ports of the locking circuit. It is revealed that the factors affecting the locking stability of DFB semiconductor laser include resonant mode hopping, polarization state hopping, and phase change of the feedback locking loop caused by external temperature and vibration, and the dominant factors are different when different types of ring resonators are used. Control of these factors can improve the stability of the selfinjection locking of DFB semiconductor lasers, so that better application effect can be achieved for the selfinjection locked DFB semiconductor laser..
Semiconductor Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 3, 552 (2022)
Research of Optimized Widebandwidth Optical Source with Er3+doped Fiber Amplified Spontaneous Emission
HAO Yunqi, JIA Ruoyi, DING Beibei, and YANG Kun
A kind of widebandwidth optical source applying amplified spontaneous emission of Er3+doped optical fiber is proposed, with bidirectional pumping and doublepass configuration. Experiments were performed to verify the proposed scheme, and then the output performance was optimized. The pump efficiency, spectrum flatnA kind of widebandwidth optical source applying amplified spontaneous emission of Er3+doped optical fiber is proposed, with bidirectional pumping and doublepass configuration. Experiments were performed to verify the proposed scheme, and then the output performance was optimized. The pump efficiency, spectrum flatness and stability were analyzed in detail. The experimental results show that the pump conversion efficiency is increased by 8.24%, the flatness of optical spectrum is improved by 1dB in 1525~1557nm without any filter，and the output linewidth @3dB is widened by 24.56nm. The stable output of optical power and spectrum within one hour is realized, which can provide light source for optical fiber sensing, spectral analysis, etc..
Semiconductor Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 3, 557 (2022)
Effect of Deposition Conditions on Microstructure and Photoelectric Properties of AZO Films by Magnetron Sputtering at Room Temperature
MO Minjing, LIU Zhe, MA Ziteng, DONG Zhihu, LIU Yong, WEI Changwei, and HE Chunqing
Aldoped ZnO (AZO) thin films were deposited on quartz glass by RF magnetron sputtering at room temperature with controlled working pressure, power and deposition time. The effects of three processing conditions on the microstructure and photoelectric properties of AZO thin films were investigated. After annealing at 5Aldoped ZnO (AZO) thin films were deposited on quartz glass by RF magnetron sputtering at room temperature with controlled working pressure, power and deposition time. The effects of three processing conditions on the microstructure and photoelectric properties of AZO thin films were investigated. After annealing at 500℃, all AZO films have hexagonal wurtzite structure and excellent transparency. The average transmittance of AZO films in visible light range is above 86%. At a pressure of 0.25Pa with the power of 200W, the resistivity of the thin film deposited for 10min is as low as 5.04×10-3Ω·cm, while the best performance index is 0.314×10-3Ω-1 for 15min. The results show that the crystal structure, square resistance and transmittance of AZO films prepared by magnetron sputtering are closely related to the working pressure, power and time during the preparation process, and the performance indexes can guide the optimization of AZO films preparation..
Semiconductor Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 3, 561 (2022)
Low Temperature Growth of Polycrystalline Molybdenum Oxide Thin Films by Atomic Layer Deposition
CHENG Tianle, CAO Fa, LI Jia, and JI Xiaohong
Polycrystalline MoO3 thin films were fabricated on silicon substrates at low temperature by plasmaenhanced atomic layer deposition (PEALD) using molybdenum hexacarbonyl and oxygen as precursors. Crystal structure, surface morphology, elemental composition of the deposited MoO3 films were characterized by XRD, SEM, AFPolycrystalline MoO3 thin films were fabricated on silicon substrates at low temperature by plasmaenhanced atomic layer deposition (PEALD) using molybdenum hexacarbonyl and oxygen as precursors. Crystal structure, surface morphology, elemental composition of the deposited MoO3 films were characterized by XRD, SEM, AFM and XPS. Results show that the crystal structure and surface morphology of the fabricated MoO3 thin films are highly dependent on the substrate temperature and the pulse time of the oxygen plasma. When the substrate temperature is 170℃ and above, the asgrown film is αMoO3. Highly (0k0) preferorientated MoO3 thin films can be obtained at 170℃ by properly prolonging the pulse time of oxygen plasma to 60s. The films are followed by the island growth mode based on the AFM analysis..
Semiconductor Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 3, 567 (2022)
Preparation and Field Emission Study of Two Kinds of Micron Diamond Polycrystalline Particle Films
GAO Jinhai, ZHANG Jie, LI Chenggang, and ZHANG Jinglin
Two kinds of micron diamond grain thin film were obtained by microwave plasma chemical vapor deposition method under different conditions. The composition of the two kinds of thin film were analyzed by Raman spectroscopy and Xray apparatus, and the surface morphology was analyzed by scanning electron microscope (SEM),Two kinds of micron diamond grain thin film were obtained by microwave plasma chemical vapor deposition method under different conditions. The composition of the two kinds of thin film were analyzed by Raman spectroscopy and Xray apparatus, and the surface morphology was analyzed by scanning electron microscope (SEM), and the field emission performance was studied by the field emission device with secondary structure. Finally, the characteristics of micron diamond films with excellent field emission properties were analyzed and discussed..
Semiconductor Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 3, 573 (2022)
Study on TemperatureBias Characteristic of Magnetic Tunnel Junctions with MoS2 Barrier
LIU Yan, FANG Henan, and LI Qian
MoS2 is a kind of twodimensional semiconductor material with unique band structure. For fewlayer MoS2, the band gap decreases significantly with the number of layers. Accordingly, the magnetic tunnel junctions (MTJs) with MoS2 barrier will show abundant and various physical properties. In this paper, the temperatureMoS2 is a kind of twodimensional semiconductor material with unique band structure. For fewlayer MoS2, the band gap decreases significantly with the number of layers. Accordingly, the magnetic tunnel junctions (MTJs) with MoS2 barrier will show abundant and various physical properties. In this paper, the temperaturebias phase diagrams are calculated, respectively, for MTJs with singlelayer MoS2, doublelayer MoS2, threelayer MoS2 and fivelayer MoS2 barrier under different half the exchange splitting of the ferromagnetic electrodes. The calculations show that, the MTJs with singlelayer and threelayer MoS2 barrier is suitable to be applied at low temperature. In particular, the MTJs with singlelayer MoS2 barrier possess excellent performance at high bias. The optimized region of MTJs with doublelayer MoS2 barrier is located at room temperature and low bias. Therefore, they are favorable for the application of information storage. Through regulating the parameter of the ferromagnetic electrodes, the MTJs with fivelayer MoS2 barrier can work throughout a wide power range. The above results lay a solid theoretical foundation for the application of MTJs with MoS2 barrier..
Semiconductor Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 3, 578 (2022)
An Adaptive Initializing Superpixel Seed Points Method Based on Kmeans++
YANG Zhili, and ZHANG Dong
As a preprocessing step of target segmentation, superpixel can greatly reduce the amount of subsequent data processing, and plays a vital role in image segmentation. In most superpixel algorithms, seed points are sampled on a regular grid or initialized randomly, which easily leads to undersegmentation. In order to oAs a preprocessing step of target segmentation, superpixel can greatly reduce the amount of subsequent data processing, and plays a vital role in image segmentation. In most superpixel algorithms, seed points are sampled on a regular grid or initialized randomly, which easily leads to undersegmentation. In order to obtain a good distribution of seed point and avoid undersegmentation, an adaptively initializing superpixel seeds method based on Kmeans++ is proposed and used to improve the algorithms of SNIC. The experimental results show that the improved SNIC algorithm can get higher boundary recall rate and lower undersegmentation error rate than that of the traditional algorithm without a lot of computational cost..
Semiconductor Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 3, 585 (2022)
Ultrahigh Dynamic Cyclic Exposure Control Technique Based on Frame Transfer CCD
WANG Ying, and ZHOU Jianyong
An exposure control technique based on frame transfer CCD is proposed to greatly improve the dynamic range in hyperspectral image detection. It adopts a new working mode of integrating first and then reading out, combined with the fast charge dumping timing control method of chargecoupled devices (CCD), which can effeAn exposure control technique based on frame transfer CCD is proposed to greatly improve the dynamic range in hyperspectral image detection. It adopts a new working mode of integrating first and then reading out, combined with the fast charge dumping timing control method of chargecoupled devices (CCD), which can effectively remove the invalid charge in the idle period and realize fast switching between the ultrashort integration time and the long integration time exposure period. For the same detected target, the uninterruptable cycle exposure of multiple exposure cycles can be realized by fast switching between multiple integral cycles within a specified time range, so that the spectrum detection range index of this technique can be improved by more than 2 orders of magnitude compared with that of the traditional technology. At the same time, the dynamic setting mode of cyclic exposure file number and exposure time is designed. The timing simulation analysis and test verifies that the proposed design can effectively improves the adaptability of hyperspectral imaging technology in complex light environment..
Semiconductor Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 3, 597 (2022)
Cooperative Offloading and Resource Allocation with MultiAgent Deep Reinforcement Learning in MEC
XIA Bingsen, TANG Yuanchun, and LI Cui
Mobile edge computing (MEC) has emerged as a key technology to alleviate the computation workloads and decrease service latency for computationintensive applications by offloading the tasks to MEC servers. However, the existing computation offloading and resource allocation studies present some several problems: poor Mobile edge computing (MEC) has emerged as a key technology to alleviate the computation workloads and decrease service latency for computationintensive applications by offloading the tasks to MEC servers. However, the existing computation offloading and resource allocation studies present some several problems: poor collaboration between edge servers; mismatch between the computational task arrival and the dynamic characteristics in the real environment; and the dynamic joint optimization problem of the collaborative task unload and resource allocation. To solve such issues, based on the collaborative MEC framework, a multiagent based deep deterministic policy gradient (MADDPG) is proposed for task unloading and resource allocation to minimize the overall longterm average cost. Simulation results reveal that the proposed scheme can reduce the delay and energy consumption..
Semiconductor Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 3, 602 (2022)
Phased Array BeamForming Based on TR Community Microwave Photonic True Time Delay Network
ZHANG Yebin, WANG Kai, and TIAN Chaohui
Due to the restriction of aperture effect and the beam deviation, it is the common problem for phased array radar to get wide instantaneous bandwidth under wide scan scope. In this paper, a phased array beam forming system based on the microwave photonic technology was proposed, which can keep high consistency between Due to the restriction of aperture effect and the beam deviation, it is the common problem for phased array radar to get wide instantaneous bandwidth under wide scan scope. In this paper, a phased array beam forming system based on the microwave photonic technology was proposed, which can keep high consistency between the beampointing of receiving and transmitting modes and reduce the number of devices. The 16 channels TR community beam scanning system was built and tested. The experimental results show the system can realize beaming scanning under the wide scope of ±30° without beam deviation at Xband, and the beampointing of receiving and transmitting is highly consistent. Combined with the timesharing receiving and transmitting characteristic of the radar system, the scanning and detection capability of the phased array radar system can be effectively improved..
Semiconductor Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 3, 609 (2022)
High Frame Rate Display Method Based on Composite Coding of Digital Micro Mirror and Illuminant
SONG Ruibo, ZHANG Tao, and CUI Wennan
As a commonly used display device, digital micromirror device (DMD) uses the traditional pulse width modulation (PWM) method to display grayscale images, which can not meet the demand of high frame rate display due to the limitation of minimum pulse width. Thus we proposed a high frame rate display technology based on As a commonly used display device, digital micromirror device (DMD) uses the traditional pulse width modulation (PWM) method to display grayscale images, which can not meet the demand of high frame rate display due to the limitation of minimum pulse width. Thus we proposed a high frame rate display technology based on composite coding of illuminant and DMD in this paper. By adding the modulation of illuminant, the problem of exponential growth of bit plane display time with bit plane level caused by pulse width modulation is avoided. A display system consists of driver module, illuminant and DMD was built. In our test, by applying the illuminant modulation to lower 4bit and pulse width modulation to higher 4bit, the display system can achieve 2461Hz frame rate displaying 8bit grayscale image..
Semiconductor Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 3, 613 (2022)
Design of Harmonic Diffractive Lens with Large Field of View Based on Infrared Band
ZHENG Yidi, HE Yiwei, LEI Boping, DU Junfeng, and YANG Hu
Aiming at the problem of increasing the number of optical elements and limiting the angle of view to balance the aberrations in the current optical design, which makes the optical system more complex, a design method of harmonic diffractive lenses based on the infrared waveband with a large field of view is proposed. TAiming at the problem of increasing the number of optical elements and limiting the angle of view to balance the aberrations in the current optical design, which makes the optical system more complex, a design method of harmonic diffractive lenses based on the infrared waveband with a large field of view is proposed. The optical design software ZEMAX was used for optical design, a customizable surface profile was written using DLL, and this surface was used for partition optimization, and combined with scalar diffraction theory, the imaging effect was analyzed. The results show that the designed harmonic diffractive lens has a field of view of 21°, and the cutoff frequency (with 0.1 as the contrast limit) is 11.4lp/mm, and the feasibility of the lens with a large field of view single lens imaging is verified through experiments..
Semiconductor Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 3, 619 (2022)
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