Self-Powered, Broad Band, and Ultrafast InGaN-Based Photodetector

A self-powered, broad band and ultrafast photodetector based on n(+)-InGaN/AlN/n-Si(111) hetero-structure is demonstrated. Si-doped (n(+) type) InGaN epilayer was grown by plasma-assisted molecular beam epitaxy on a 100 nm thick AlN template on an n-type Si(111) substrate. The n(+)-InGaN/AlN/n-Si(111) devices exhibit excellent self-powered photoresponse under UV-visible (300-800 nm) light illumination. The maximum response of this self-powered photodetector is observed at 580 nm for low-intensity irradiance (0.1 mW/cm(2)), owing to the deep donor states present near the InGaN/AlN interface. It shows a responsivity of 9.64 A/W with rise and fall times of 19.9 and 21.4 mu s, respectively. A relation between the open circuit voltage and the responsivity has been realized.