InGaAsN Metal-Semiconductor-Metal Photodetectors with Transparent Indium Tin Oxide Schottky Contacts

摘要

GaAs-based photodetectors (PDs) draw much attention owing to several advantages, such as low fabrication cost and the mature process techniques. However, fabricating them is a difficult task for the lack of suitable absorption materials that can be coherently grown on the GaAs substrate. In this report, we provide another approach to fabricate GaAs-based PDs, in which the novel InGaAsN alloy is used as the absorption layer. Three structures of planar PDs were demonstrated using transparent indium tin oxide (ITO) contacts. The dark current of PDs were suppressed by applying the SiO_2 Schottky-barrier enhancement layer, but the rough interface between the SiO_2 and InGaAsN layer limited the device characteristics. Depositing a thin layer of ITO between the SiO_2 and InGaAsN layers greatly improved the interface quality and the photo current-to-dark current ratio was also increased from 17.7 to 45.29 under 0.5 V bias.