Room Temperature InAs_xP_1-x-ySb_y/InAs Photodetectors with High Quantum Efficiency

Abstract

Room temperature surface-illuminated InAs x P 1- x - y Sb y /InAs photodiodes with an external quantum efficiency as high as 50–86% in a 1.83–3.53 µm wavelength range have been fabricated for the first time. Lattice matched heterostructures with a wide energy gap InAsPSb cap layer were grown on the InAs substrate using the liquid phase epitaxy technique. According to temperature dependence measurements for a 1 mm diameter photodiode, peak responsivities of 1.83–2.5 A/W have been realized in a temperature range of 296 to 200 K. The Johnson noise limited room temperature detectivities D * are deduced to be 1\endash6 ×10 9 cm·Hz 1/2 /W at zero bias. It is demonstrated that the only loss of external quantum efficiency is from the reflection of the entrance face.