InGaN Metal-Semiconductor-Metal Photodetectors With Aluminum Nitride Cap Layers

We report on the fabrication and characterization of InGaN metal-semiconductor-metal photodetectors (PDs) by using triethylgallium gallium source for the growth of InGaN active layers and in-situ aluminum nitride as cap layers. Improved characteristics such as reduced dark leakage current, large ultra violet (UV)-to-visible rejection ratio, low noise level, and high detectivity can be achieved in our devices. Current transport mechanisms in InGaN PDs were also investigated. Fowler-Nordheim mechanism associated with the defect-related tunneling should be included besides the traditional thermionic emission model.