InGaAs-GaAs Nanowire Avalanche Photodiodes Toward Single-Photon Detection in Free-Running Mode.

Single-photon detection at near-infrared (NIR) wavelengths is critical for light detection and ranging (LiDAR) systems used in imaging technologies such as autonomous vehicle trackers and atmospheric remote sensing. Portable, high-performance LiDAR relies on silicon-based single-photon avalanche diodes (SPADs) because of their extremely low dark count rate (DCR) and afterpulsing probability, but their operation wavelengths are typically limited up to 905 nm. Although InGaAs-InP SPADs offer an alternative platform to extend the operation wavelengths to eye-safe ranges, their high DCR and afterpulsing severely limit their commercial applications.

Diode Characteristics Approaching Bulk Limits in GaAs Nanowire Array Photodetectors.

We present the electrical properties of p-n junction photodetectors comprised of vertically oriented p-GaAs nanowire arrays on the n-GaAs substrate. We measure an ideality factor as low as n = 1.0 and a rectification ratio >10 across all devices, with some >10, comparable to the best GaAs thin film photodetectors.