Design and Fabrication of a Photodetector for UV/Blue Wavelength Region for Low-Light Intensity Levels Using InGaN/GaN Superlattice Structure

Photodetectors (PDs) are photo-responsive devices, which are frequently used in a variety of applications such as consumer electronics, space research, environmental monitoring, optical communication, and so on, for decades. However, still there is a need to better the performance of these PDs, especially for UV and blue regions that can operate at comparatively low-light levels of around
$\mu $
W/cm2. The present work is dedicated to the design and analysis of the PD for the above-mentioned purpose using Group-III nitride compound semiconductors. This work includes both the experimental design and simulation of a UV PD to have good responsivity, low dark current, good sensitivity, and quantum efficiency (QE) in UV to blue (visible) wavelength regions, i.e., 350–450 nm as figures of merit that can be used for a variety of applications which require detection under low-light intensity levels. As Group-III nitrides bandgap can be suitably tuned for UV/blue regions, they are widely used for the detection of UV spectrum. The present PD is implemented using the InGaN/GaN superlattice structure, which acts as the active region in the proposed p-i-n structure. The device achieved the external QE of 52.19% at 385 nm for an incident wave of intensity
$1~\mu $
W/cm2. The dark and photo current for the fabricated device is found out to be 78 pA and 161.74 nA at 2.4 V of applied bias. The results have shown that the structure indeed has a capability of commercialization as its parameters meet the requirements of low-light intensity detection.