Spectral Sensitivity Tuning of Vertical InN Nanopyramid-Based Photodetectors

Abstract

In this paper, we report on the fabrication of InN nanopyramid-based photodetectors operating within the telecommunication wavelength range. We found that the spectral sensitivity of individually addressable InN nanopyramids can be tuned within an interval of 1550–1750 nm since the band edge luminescence energy correlates with the structure size. According to this, we optimized the nanopatterning technique of SiO 2 /GaN/sapphire substrates as well as the selective area growth to precisely control the nanostructure dimensions. Furthermore, we developed a technological process to contact InN nanopyramids and to integrate them into a high-frequency device layout. Thus, InN nanopyramid-based photodetectors exhibit a low R C constant, low dark currents below 1 nA, as well as a high responsivity of about 0.2 A/W at a wavelength of 1.55 µm.