Flexible Transient Phototransistors by Use of Wafer‐Compatible Transferred Silicon Nanomembranes

Flexible transient photodetectors, a form of optoelectronic sensors that can be physically self‐destroyed in a controllable manner, could be one of the important components for future transient electronic systems. In this work, a scalable, device‐first, and bottom‐up thinning process enables the fabrication of a flexible transient phototransistor on a wafer‐compatible transferred silicon nanomembrane. A gate modulation significantly restrains the dark current to 10 −12 A. With full exposure of the light‐sensitive channel, such a device yields an ultrahigh photo‐to‐dark current ratio of 10 7 with a responsivity of 1.34 A W −1 (λ = 405 nm). The use of a high‐temperature degradable polymer transient interlayer realizes on‐demand self‐destruction of the fabricated phototransistors, which offers a solution to the technical security issue of advanced flexible electronics. Such demonstration paves a new way for designing transient optoelectronic devices with a wafer‐compatible process.