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Contents
2001
Volume: 20 Issue 1
15 Article(s)
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Research Article
SHORTWAVE LIMIT OF INFRARED INTERSUBBAND QUANTUM CASCADE LASERS
[in Chinese], [in Chinese], and [in Chinese]
The feasibility and fundamental difficulty in developing the infrared intersubband quantum cascade lasers in shorter wavelength range were discussed theoretically. The band offsets of InAs/AlSb on GaSb substrate, InAs/Al0.6Ga0.4Sb on GaSb substrate, and In0.53Ga0 .47As/In0.52Al0.48As on InP substrate, and the confined The feasibility and fundamental difficulty in developing the infrared intersubband quantum cascade lasers in shorter wavelength range were discussed theoretically. The band offsets of InAs/AlSb on GaSb substrate, InAs/Al0.6Ga0.4Sb on GaSb substrate, and In0.53Ga0 .47As/In0.52Al0.48As on InP substrate, and the confined states of their quantum wells with and without an applied electric field were analyzed and calculated by using the fundamental assumption of model-solid theory, strained band structure theory, empirical-two-band model for non-parabolic band, and methods of propagation matrix and laminar approach. It was found that the greatest energy difference between subband edges can not exceed 56～62% of the conduction band offset, and will be decreased further by the indirect valley. A designed structure of intersubband quantum cascade laser consisting of 250 coupled quantum wells in 25 periods under electric field 100kV/cm for emitting the shortest wavelength 2.88μm was proposed..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2001
- Vol. 20, Issue 1, 1 (2001)
XAFS STUDIES ON LOCAL STRUCTURES OF NANOCRYSTALLINE AND CRYSTALLINE GaN
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
X-ray absorption fine structure (XAFS) was used to investigate the local structures around Ga atoms in the hexagonal nanocryst alline and crystalline GaN under 78K and 300K. For the first nearest-neighbor coordination of Ga-N, the average bond length R, coordination N, thermal disorder σT and structural disorder σS of X-ray absorption fine structure (XAFS) was used to investigate the local structures around Ga atoms in the hexagonal nanocryst alline and crystalline GaN under 78K and 300K. For the first nearest-neighbor coordination of Ga-N, the average bond length R, coordination N, thermal disorder σT and structural disorder σS of nanocrystalline GaN ar e similar to those of crystalline GaN, which are 0.194nm, 4.0,0.0052nm and 0.000 7nm, respectively. When the temperature is elevated from 78K to 300K, the σT in GaN samples increases by lower than 0.0005nm. It indicates that the Ga- N covalent bond is much stronger, and is nearly independent of temperature and c rystalline state. For the second nearest-neighbor Ga-Ga coordination, the R values of the samples are about 0.318nm; the σS(0.0057nm) of nanocryst alline GaN is 0.0047nm larger than that of crystalline GaN(0.001nm); the σT of Ga-Ga coordination in nanocrystalline GaN are 0.0053nm, 0.0085nm for the temperature of 78K and 300K, respectively. This shows that the σT of Ga- Ga coordination is greatly affected by the temperature. The major difference of local structure around Ga atoms between nanocrystalline GaN and crystalline GaN is shown by the relatively large σS of the Ga-Ga second nearest-neighbo r shell in nanocrystalline GaN. The reason may be explained by that there exist larger defects and unsaturated surface atoms in nanocrystalline GaN..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2001
- Vol. 20, Issue 1, 7 (2001)
PHONON-INDUCED RAMAN SCATTERING IN GaNAs
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The Raman scattering spectra of MBE-grown GaNA s epilayers were investigated. The resonant enhancement of Raman scattering due to the E+ states in the conduction band was observed and the Raman peaks r elated to the phonons at non-Γ points of the Brillouin Zone were detected.It w as clearly seen that the local vibratioThe Raman scattering spectra of MBE-grown GaNA s epilayers were investigated. The resonant enhancement of Raman scattering due to the E+ states in the conduction band was observed and the Raman peaks r elated to the phonons at non-Γ points of the Brillouin Zone were detected.It w as clearly seen that the local vibrational mode induced by nitrogen impurities e volves to the GaN-like lattice phonon mode when the nitrogen content increases. By comparing the Raman spectra measured before and after 850℃ rapid thermal an nealing, it was tentatively suggested that two weak peaks were induced by the pa iring or clustering effect of nitrogen..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2001
- Vol. 20, Issue 1, 11 (2001)
STRUCTURAL RESONANCES IN RAMAN SPECTRUM OF TiBa GLASS MICROSPHERE
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The Raman spectra of TiBa glass plate and TiBa glass microsphere were measured and the structural resonance in Raman spectrum o f glass microsphere was found. According to the microcavity theory, the structur al resonance was analyzed, and the Mie scattering theory was used to fit the exp erimental results, showing theThe Raman spectra of TiBa glass plate and TiBa glass microsphere were measured and the structural resonance in Raman spectrum o f glass microsphere was found. According to the microcavity theory, the structur al resonance was analyzed, and the Mie scattering theory was used to fit the exp erimental results, showing the investigated microsphere diameter of 25.01μm and the refractive index of 1.895 at a wavelength close to 632.8 nm (with a Raman s hift of 300cm-1).
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2001
- Vol. 20, Issue 1, 30 (2001)
MAGNETO-OPTICAL KERR EFFECT OF Mn/Sb MULTILAYER FERROMAGNETIC FILMS ON GaAs SUBSTRATE
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Mn/Sb multilayer films were grown on (100) GaAs substrate by an ultrahigh vacuum evaporation system and were annealed for a short time. The magnetic and magneto-optical properties were investigated for the samples unannealed and annealed, respectively. All unannealed Mn/Sb multilayer f ilms exhibit strong ferromagneticMn/Sb multilayer films were grown on (100) GaAs substrate by an ultrahigh vacuum evaporation system and were annealed for a short time. The magnetic and magneto-optical properties were investigated for the samples unannealed and annealed, respectively. All unannealed Mn/Sb multilayer f ilms exhibit strong ferromagnetic properties and the easy magnetization axes are in-plane. The surface of the samples consists of dense islands. The longitudin al (H∥ plane) Kerr effect was not observed for the unannealed samples. All samples annealed at 350℃ for 20min were found to be single phase with nickel ar senide (NiAs) crystal structure and have the largest saturation magnetization Ms and the lowest coercive force Hc. The magnetic force microscope ima ge shows uniform ferromagnetic properties of the film. The longitudinal magneto -optical Kerr effect was observed. The observable Kerr effect hysteresis loop c an be obtained for the annealed Mn/Sb multilayer films on GaAs..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2001
- Vol. 20, Issue 1, 33 (2001)
EFFECTIVE MASS OF THE ELECTRON-SURFACE PHONONS STRONG- COUPLING MAGNETOPOLARON IN A SLAB OF POLAR CRYSTAL WITHIN CONSTANT MAGNETIC FIELDS
[in Chinese], and [in Chinese]
The effective mass of the magnetopolaron in a slab of polar crystal within constant magnetic fields, which is a weak coupling of electron-bulk longitudinal optical (LO) phonons and strong coupling of electron-surface optical (SO) phonons, was discussed by using Tokuda's improved linear combination operator and the The effective mass of the magnetopolaron in a slab of polar crystal within constant magnetic fields, which is a weak coupling of electron-bulk longitudinal optical (LO) phonons and strong coupling of electron-surface optical (SO) phonons, was discussed by using Tokuda's improved linear combination operator and the Lagrange multiplier and the variational method. The effective mass of the magnetopolaron was obtained as a function of the slab thickness and the magnetic fields. Numerical calculations for KC1 polar crystal slab show that the effective mass of the magnetopolaron first decreases and then increases, finally tends to a stable value with increasing slab thickness, and increases with increasing magnetic fields..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2001
- Vol. 20, Issue 1, 37 (2001)
INVESTIGATION ON InGaAs/InAlAs QUANTUM CASCADE LASERS ZHANG Quang-Sheng（National Integrated
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The preparation and main characteristics of the InGaAs/InAlAs quantum cascade laser were given. The device has a reinforced ridge waveguide structure. The threshold current obtained at 80K is about 0.5A, an d the corresponding threshold current density is about 5kA/cm2.The preparation and main characteristics of the InGaAs/InAlAs quantum cascade laser were given. The device has a reinforced ridge waveguide structure. The threshold current obtained at 80K is about 0.5A, an d the corresponding threshold current density is about 5kA/cm2..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2001
- Vol. 20, Issue 1, 41 (2001)
SPECTRAL PROPERTIES OF Sm3+IN Cd3Al2Si3O12 GLASS
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Sm-doped Cd3Al2Si3O12glass was synthesized by solid state reaction. The transmittance spectrum, emission spectra, excitation spectra and near infrared emission spectra of the glass with the excitation of 488nm Ar+ laser were measured at room temperature. The spectral prop erties of Sm3+ ions in the glass were investigaSm-doped Cd3Al2Si3O12glass was synthesized by solid state reaction. The transmittance spectrum, emission spectra, excitation spectra and near infrared emission spectra of the glass with the excitation of 488nm Ar+ laser were measured at room temperature. The spectral prop erties of Sm3+ ions in the glass were investigated. Under 365nm, the sampl e emits intense orange-red light peaked at 603nm due to4G5/2→6H9/2 transition. With the excitation of 488nm Ar+ laser, the sample gives rise to intense near infrared emission at about 1202.5, 1293.5 and 957.5nm..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2001
- Vol. 20, Issue 1, 44 (2001)
PHOTOLUMINESCENCE STUDIES OF TYPE-Ⅱ SELF-ASSEMBLED InAl As/AlGaAs QDs GROWN ON (311)A GaAs SUBSTRATE
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The photoluminescence (PL) spectra of self-assembled In0.55Al0.45As/Al0.5Ga0.5As quantum dots (QD) grown on (311)A GaAs substrate were measured. The type-Ⅱ character of PL related to the X valley was verified by excitation power dependence of peak position and the PL spectra under different pressure, which was attributThe photoluminescence (PL) spectra of self-assembled In0.55Al0.45As/Al0.5Ga0.5As quantum dots (QD) grown on (311)A GaAs substrate were measured. The type-Ⅱ character of PL related to the X valley was verified by excitation power dependence of peak position and the PL spectra under different pressure, which was attributed to the type-Ⅱ transition from X valley in Al0.5Ga0.5As to heavy holes in In0. 55Al0.45As.The high energy Γ-related transition was also observed above 70K and aasigned as the transition between Γ valley and heavy holes in In 0.55Al0.45As.The X-valley split was discussed to interpret the observed second X-related peak under pressure..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2001
- Vol. 20, Issue 1, 53 (2001)
OPTICAL AND MAGNETO-OP TICAL PROPERTIES OF NixSiO2(1-x) GRANULAR FILMS ZHANG Rong-Jun（Optical Science and Engineering
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A series of NixSiO2(1-x) granular films were made by a magnetron rf sputtering system with variation of x and the annealing process. Both the complex dielectric function and magneto-optical polar Kerr spectra of the samples were me asured at room temperature in the 1.5～4.5eV photon energy range, respectively. I t was fA series of NixSiO2(1-x) granular films were made by a magnetron rf sputtering system with variation of x and the annealing process. Both the complex dielectric function and magneto-optical polar Kerr spectra of the samples were me asured at room temperature in the 1.5～4.5eV photon energy range, respectively. I t was found that there are new spectral features in the dielectric functions. The ε1 spectra change continuously from positive to negative at the low photon energy range in these metal-insulator granular films by adjusing the composition or by the annealing process. For the NixSiO2(1-x) samples, there are broad peaks in the Kerr rotation and ellipticity spectra. The Kerr in tensities increase with increasing Ni composition. Both the off-diagonal terms of the dielectric terms tensor and optical constants play important role in th e enhancement of the Kerr effect in a particular spectral range for the metal-i nsulator granular films..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2001
- Vol. 20, Issue 1, 57 (2001)
FANNING NOISE SUPPRESSION IN DUAL- WAVELENGTH HOLOGRAPHIC STORAGE
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
It was shown how the fanning noise is reduced by the dual-wavelength method in the photorefractive crystals. The non -destructive readout can be realized. The experiments were first done with lithium niobate doped with iron to find the optimal reading out configuration. After wards lithium niobate doped with iron and mIt was shown how the fanning noise is reduced by the dual-wavelength method in the photorefractive crystals. The non -destructive readout can be realized. The experiments were first done with lithium niobate doped with iron to find the optimal reading out configuration. After wards lithium niobate doped with iron and magnesium was used to record the high signal-to-noise-ratio holograms. In order to retrieve the hologram with filed losses a cylindrical lens was added into the reference path..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2001
- Vol. 20, Issue 1, 61 (2001)
PHOTOLUMINE SCENCE CHARACTERIZATION IN GaAs/AlGaAs QUANTUM WELL INFRARED PHOTODETECTORS
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Micro-photoluminescence (μ-PL) measurement w as performed on GaAs/AlGaAs quantum well infrared photodetectors (QWIPs). The PL peaks in the multi-quantum wells (MQWs), which reveal the energy positions of band-to-band transitions in the barrier and the well, respectively, are directly related to the Al component in the Micro-photoluminescence (μ-PL) measurement w as performed on GaAs/AlGaAs quantum well infrared photodetectors (QWIPs). The PL peaks in the multi-quantum wells (MQWs), which reveal the energy positions of band-to-band transitions in the barrier and the well, respectively, are directly related to the Al component in the barrier of AlxGa1-xAs. Us ing standard effective mass theory for quantum wells the realistic Al compone ntx and well widthd were deduced. Consequently the peak response wavel ength λp of the QWIP was determined. The calculated λp is coincide nt with the result from photocurrent spectrum for the same sample very well. It proves that the present method is very applicable for the MQW materials con trol in the process of device fabrication..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2001
- Vol. 20, Issue 1, 66 (2001)
OPTICAL PROPERTIES OF Pb1-xGexTe FILMS
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Study of Pb1-xGexTe films deposited by PVD revealed that Pb1-xGexTe is a kind of fine characteristic infrared materials, which has a high transmission in the spectral range 3～ 25μm, and has indices of refraction in the range 4.8～5.6 at room temperature . Optical properties, which include transmission spectrum, dispersiStudy of Pb1-xGexTe films deposited by PVD revealed that Pb1-xGexTe is a kind of fine characteristic infrared materials, which has a high transmission in the spectral range 3～ 25μm, and has indices of refraction in the range 4.8～5.6 at room temperature . Optical properties, which include transmission spectrum, dispersion spectrum and temperature coefficient dn/dT of refractive index, depend strongly on content x, environmental temperature and deposition conditions. It can be found that proper change of content x and deposition conditions may result in the change of temperature coefficient dn/dT of refractive index from negative to zero, and to positive from zero, which is of significance for manufacturing highly stable infrared optical filters..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2001
- Vol. 20, Issue 1, 69 (2001)
PREPARATION OF (Ba0.5Sr0.5)TiO3 THIN FILM BY SOL-GEL TECHNIQUE AND ITS CHARACTERISTICS
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
(Ba0.5Sr0.5)TiO3 ferroelectric thin films were prepared by Sol-Gel processing. Films with thickness of 160nm treated at 700℃ for 1h showed pure perovskite structure and good dielectric, insulating properties, i.e. a dielectric constant of 225, a dielectric loss of 0.04 4, a leakage current density of 8.0×10－8A/cm2(Ba0.5Sr0.5)TiO3 ferroelectric thin films were prepared by Sol-Gel processing. Films with thickness of 160nm treated at 700℃ for 1h showed pure perovskite structure and good dielectric, insulating properties, i.e. a dielectric constant of 225, a dielectric loss of 0.04 4, a leakage current density of 8.0×10－8A/cm2. The leakage current density was found to depend on the annealing temperature. The measurement of the J-V characteristics on films indicated the conduction process to be bulk- limited..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2001
- Vol. 20, Issue 1, 73 (2001)
TEMPERATURE DEPENDENCE OF THE ACOUSTIC DEFORMATION POTENTIAL SURFACE POLARON
[in Chinese], and [in Chinese]
The temperature characteristic of the acoustic deformation potential surface polaron in polar crystal, which has a weak coupling with surface phonons and a strong coupling with surface optical phonons was studied by using linear-combination-operator method.Numerical calculation for KI crystal as an example, illustratedThe temperature characteristic of the acoustic deformation potential surface polaron in polar crystal, which has a weak coupling with surface phonons and a strong coupling with surface optical phonons was studied by using linear-combination-operator method.Numerical calculation for KI crystal as an example, illustrated that the vibration frequency λ and effective mass m*2 of the acoustic deformation potential surface polaron decrease with increasing temperature, but the induced potential Vai of the acoustic deformation potential surface polaron will increase with increasing temperature..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2001
- Vol. 20, Issue 1, 77 (2001)
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