Semiconductor p–n junctions provide rectification behaviour and act as building blocks in many electronic devices. However, the typical junction configuration restricts the potential functionalities of devices. Here we report a light-detection electrochemical cell that is based on vertically aligned p-AlGaN/n-GaN p–n heterojunction nanowires in an electrolyte environment. After decorating the nanowires with platinum nanoparticles, the cell exhibits a photoresponse in which the photocurrent polarity is reversed depending on the wavelength of light. In particular, illumination of the device at two different wavelengths (254 nm and 365 nm) triggers different redox reactions at the nanowire/electrolyte interface, inducing polarity reversal of the photocurrent. The device offers a responsivity of up to −175 mA W⁻¹ at 254 nm and 31 mA W⁻¹ at 365 nm, both at 0 V.

半导体 p-n 结提供整流行为并在许多电子设备中充当构建块。然而，典型的结配置限制了器件的潜在功能。在这里，我们报告了一种基于垂直排列的 p-AlGaN/n-GaN p-n 异质结纳米线在电解质环境中的光检测电化学电池。在用铂纳米粒子装饰纳米线后，电池表现出光响应，其中光电流极性根据光的波长而反转。特别是，以两种不同波长（254 nm 和 365 nm）照射器件会在纳米线/电解质界面处触发不同的氧化还原反应，从而引起光电流的极性反转。该器件提供高达 -175 mA W ^{-1的响应度}在 254 nm 和 31 mA W ^-1在 365 nm，均为 0 V。