Homo- and heterojunctions play essential roles in semiconductor-based devices such as field-effect transistors, solar cells, photodetectors and light-emitting diodes. Semiconductor junctions have been recently used to optically trigger biological modulation via photovoltaic or photoelectrochemical mechanisms. The creation of heterojunctions typically involves materials with different doping or composition, which leads to high cost, complex fabrications and potential side effects at biointerfaces. Here we show that a porosity-based heterojunction, a largely overlooked system in materials science, can yield an efficient photoelectrochemical response from the semiconductor surface. Using self-limiting stain etching, we create a nanoporous/non-porous, soft–hard heterojunction in p-type silicon within seconds under ambient conditions. Upon surface oxidation, the heterojunction yields a strong photoelectrochemical response in saline. Without any interconnects or metal modifications, the heterojunction enables efficient non-genetic optoelectronic stimulation of isolated rat hearts ex vivo and sciatic nerves in vivo with optical power comparable to optogenetics, and with near-infrared capabilities.

同质结和异质结在场效应晶体管、太阳能电池、光电探测器和发光二极管等半导体器件中发挥着重要作用。半导体结最近已被用于通过光伏或光电化学机制光学触发生物调制。异质结的产生通常涉及具有不同掺杂或成分的材料，这导致高成本、复杂的制造和生物界面的潜在副作用。在这里，我们展示了基于孔隙率的异质结，这是材料科学中一个很大程度上被忽视的系统，可以从半导体表面产生有效的光电化学响应。使用自限染色蚀刻，我们在环境条件下在几秒钟内在 p 型硅中创建了纳米多孔/无孔、软硬异质结。表面氧化后，异质结在盐水中产生强烈的光电化学响应。在没有任何互连或金属修饰的情况下，异质结能够对离体大鼠心脏和体内坐骨神经进行有效的非遗传光电刺激，具有与光遗传学相当的光功率和近红外能力。