Indium composition effects on extended short-wave infrared photodetector performance

Abstract

In this study, cutoff wavelengths of 2.7 µm, 3.0 µm and 3.2 µm were achieved in an extended short wavelength infrared In_xGa_1-xAs photodetector using different indium compositions in the In_xGa_1-xAs active layer. We compared and analyzed the resulting characteristics as a function of indium composition in In_xGa_1-xAs ternary alloys. The spectral response and the dark current of the detector have been analyzed in the temperature range from 200 to 300 K with a step of 10 K. It was found that the energy of the bandgap decreases and the cutoff wavelength shifts to a longer wavelength region with a higher indium composition. The temperature coefficient of the cutoff wavelength increases with indium composition. The dark current behavior dominated by trap-assisted tunneling at high indium composition results in a negative differential resistance. By keeping the doping concentration constant, the responsivity did not change significantly with the indium composition. However, the detectivity varied. This study provides valuable insights into the design and optimization of scalable extended short wavelength infrared photodetectors for various infrared applications.