UNPASSIVATED HIGH OPERATING TEMPERATURE GaInAsSb INFRARED DETECTOR PHOTODETECTOR GROWN ON GaAs SUBSTRATE

Abstract

Ga 0.87 In 0.13 As 0.4 Sb 0.96 photodiode structure was grown on semi-insulating 4” GaAs substrate by molecular beam epitaxy. The composition, crystal quality and dislocation density of epilayers were determined by high resolution X-ray diffraction rocking curve measurements. The threading dislocation density of the photodetector structure was calculated from the rotational broadening as ~2.5x10 8 cm -2 . The cutoff wavelength and the peak responsivity of the photodetector were determined as around 2.15 μm and 0.08 A/W at 300 K, respectively. By applying reverse bias (-100 mV) the responsivity value of the photodetector increases more than an order (~0.96 A/W) which is the best value reported up to now. Those results indicate that although there is a large lattice mismatch (~8.4%) between GaAs substrate and the photodetector structure, an acceptable photodetector performance was achieved which is important for reducing photodetector costs.