Spectral Sensitivity Tuning of Vertical InN Nanopyramid-Based Photodetectors

摘要

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 RC constant, low dark currents below 1 nA, as well as a high responsivity of about 0.2 A/W at a wavelength of 1.55μm.