Suspended waveguide photodetector featuring p-n junction InGaN/GaN multiple quantum wells

Abstract

In this paper, we report on the fabrication and characterization of a suspended waveguide photodetector featuring p-n junction InGaN/GaN multiple quantum wells (MQWs) on a GaN-on-silicon platform. Both silicon removal and back wafer etching are conducted to achieve the suspended waveguide photodetector combination. The light illumination measurements experimentally demonstrate that the metallization stacks can serve as the bottom metal mirror to reflect the incoming light back for re-absorption, leading to an improved photocurrent response. The out-of-plane light can couple into the suspended waveguide and propagate as a confined optical mode, resulting in an induced photocurrent. The photodetector exhibits two operation modes. The peak values of the responsivity spectra for the suspended waveguide photodetector are located around 401 nm at 3 V bias and 435 nm at 0 V bias, respectively. These results pave a promising way to develop the suspended waveguide photodetector for diverse applications in the visible wavelength region.