Photoelectric characteristics of diodes in prototype photosensitive pixels for a monolithic array infrared photodetector

Test photodiodes in the form of mesa structures with different areas from 30 $\times$ 30 to 100 $\times$ 100 $\mu$m in size are fabricated based on a Cd$_x$Hg$_{1-x}$Te/Si structure at $\times$ = 0.235, grown by molecular-beam epitaxy (MBE). The current-voltage characteristics of the diodes are measured in the dark and under background light conditions. The experimental results are compared with theoretical calculations. It is found that the dependence of the photodiode photocurrent and dark current on the mesa structure size appears in the mesa size ranges from 30 $\times$ 30 to 80 $\times$ 80 $\mu$m. The dark current decreases and the photocurrent increases with decreasing mesa size. The mechanisms affecting the behavior of current-voltage characteristics are discussed.