Back-side illuminated Ga0.47In0.53As photoconductive detectors and associated dark zones

Abstract
We report the first back‐side illuminated Ga0.47In0.53As photoconductive detector. The scheme of back‐side illumination has led to an improvement of 1.5 dB in responsivity over front‐side illumination. Furthermore, we observed dark zones where responsivities showed a minimum in the vicinity of negative electrodes. Responsivities appeared to peak at the positions beneath the positive electrodes due to a reduction in electron transit time. The upper limit of electrode widths to achieve high‐performance back‐side illuminated devices was also calculated.