Fabrication of Crack-Free Metal-Semiconductor-Metal Ultraviolet Photodetectors on Si (111) Substrates Based on Novel AlN/AlGaN Buffer Multilayer Scheme

摘要

The GaN ultraviolet metal-semiconductor-metal (MSM) photodetectors epitaxially grown on Si (111) and sapphire (0001) substrates were prepared and characterized. By implementing our elaborate AlN/AlGaN buffer multilayer scheme on Si, the maximum responsivity of n-GaN MSM photodetector with TiW transparent electrodes achieved at an incident wavelength of 359nm was 0.187A/W, which corresponds to the quantum efficiency of 64.7%. Furthermore, for a given bandwidth of 1kHz and a given bias of 5V, the corresponding noise equivalent power (NEP) of aforementioned photodetector was 1.53×10{sup}(-12)W, which translates to a maximal detectivity (D*) of 1.31×10{sup}12cm-Hz{sup}0.5W{sup}(-1).