High responsivity and high speed InGaN-based blue-light photodetectors on Si substrates

Due to the adjustable band gap, the excellent radiation stability, and the high electron mobility of InGaN, the InGaN-based blue-light photodetectors (PDs) show great potential in visible light communication (VLC) systems. However, the applications of InGaN-based blue-light PDs in VLC systems are limited by the poor performance caused by the poor crystalline quality of InGaN materials. Herein, we report on the fabrication of high responsivity and high response speed InGaN-based metal-semiconductor metal (MSM) blue-light PDs using high-quality InGaN epitaxial films grown on Si substrates by the combination of low-temperature pulsed laser deposition (LT-PLD) and high-temperature metal organic chemical deposition (HT-MOCVD). The technology can not only suppress the interfacial reactions between films and substrates by LT-PLD growth, but also promote the lateral overgrowth of InGaN and improve the crystalline quality of InGaN-based epitaxial films by HT-MOCVD growth. Based on the high-quality InGaN-based materials, high-performance InGaN-based blue-light PDs are fabricated accordingly with a high responsivity of 0.49 A W^-1 and a short rise/fall response time of 1.25/1.74 ms at an applied bias of -3 V. The performance is better than the results for the InGaN-based PDs previously reported. The InGaN-based blue-light PDs shed light on the potential for VLC system applications.