Fig. 1. Schematic epi-structures of InGaN-based orange LEDs on silicon(111) substrates: (a) Sample A with nine orange QWs and (b) Sample B with two orange QWs and seven yellow QWs. (c) TEM image of a cross section near the active region of Sample B. For easier presentation, the full thicknesses of n-GaN and p-GaN are not shown.

Fig. 2. Room temperature electroluminescence spectra of (a) Sample A and (b) Sample B, where lines 1 to 9 correspond to a current density of 0.4, 0.8, 1.5, 2.0, 3.0, 4.0, 5.5, 7.5, and 10.0  A/cm2, respectively.

Fig. 3. (a) Room temperature dependence of WPE on the current density of InGaN-based orange LEDs on silicon(111) substrates. Emission photos of (b) Sample B and (c) Sample A driven at a current density of 0.8  A/cm2.

Fig. 4. Fluorescence luminescence images of InGaN-based orange LEDs on silicon(111) substrates, (a) Sample A and (b) Sample B, under an excited lamp source with a wavelength range from 510 to 560 nm.

Fig. 5. Dependence of (a) WPE, (b) FWHM, and (c) voltage on the peak wavelength of InGaN-based orange and red LEDs at room temperature and at a current density of 0.8  A/cm2.