Fabrication and photoresponsive characteristics of ultraviolet GaN p-i-n photodetector based AlN:Al2O3 passive layer

In this manuscript, GaN ultraviolet (UV) photodetector was fabricated through pulsed laser deposition (PLD) technique considering AlN:Al2O3 as a passive layer. Further, a detailed interdependence between the corresponded microstructural features of the deposited layer/s and the photoresponsive analysis of the fabricated UV photodetector is systematically demonstrated. In detail, an alteration in the photoluminescence-based optical band gap of 0.05 eV resulted in an enhanced photocurrent from 1.2 to 8 mu A, respectively, for GaN/Si and GaN/ AlN:Al2O3/Si devices; this in turn indicates the active role of the utilized passive layer. The investigated figure of merits, photo-responsivity (R) in particular, revealed a considerable increment from 38.5 to 53.7 mu A/W for the pronounced geometries, respectively. The time-resolved characteristics demonstrated considerably fast and reproducible profile over three multiple cycles with an enhanced switching behavior (similar to 100 ms). Specifically, a response time of 800 ms was noticed for pristine device wherein photodetector attained with passive layer exhibited response time of 700 ms.