Selective-area nanowire photodetectors: from near to mid-wavelength infrared (Conference Presentation)

Semiconductor nanowires are frequently highlighted as promising building blocks for next-generation optoelectronic devices. In this study, we explore infrared photodetectors based on selective-area nanowire arrays, spanning the wavelength spectrum from near-infrared (NIR) to mid-wavelength infrared (MWIR). Examples of these nanowire detectors include: NIR GaAs photodiodes, NIR InGaAs avalanche photodetectors (APDs), NIR InGaAs-GaAs single-photon photodiodes (SPADs), short-wavelength infrared (SWIR) InAs photodiodes, and MWIR InAsSb photodiodes. The small fill factor of nanowire arrays, i.e., the small junction area, is advantageous as it causes significant suppression of dark current, which further decreases the noise level and increases the detectivity. In addition, by utilizing metal nanostructures as 3D plasmonic gratings, we can enhance optical absorption in nanowires through excitation of surface plasmonic waves at metal-nanowire interfaces. Our work shows that, through proper design and fabrication, nanowire-based photodetectors can demonstrate equivalent or better performance compared to their planar device counterparts.