Analyzing extended wavelength InGaAs photodetectors: the effects of window and active layer thickness on optical characteristics

This study investigates the effect of the absorber and window layers on the quantum efficiency and optical performance of InGaAs-based photodetectors. In the theoretical part, the quantum efficiencies of samples with different absorbers and window layers were simulated using the FDTD method. After optimizing the absorber and window layers, three samples with various absorber and window configurations were manufactured using the low-pressure-organic chemical vapor deposition technique, and the high-resolution X-ray diffraction spectrum was conducted to confirm the structural characteristics of the samples. Photoluminescence measurements were used to examine their optical performance. Temperature- and power-dependence of the photoluminescence spectra of the samples were studied for a variety of temperatures and powers, and the relevant optical characteristics were extracted. The theoretical results and the experimental outcomes from photoluminescence reveal that the thicknesses of the window and absorber layers play a crucial role in the performance of the structures. The comparison of the samples’ optical behavior and quantum efficiency results can provide valuable insights into achieving high-performance photodetectors.