Rippled Metallic‐Nanowire/Graphene/Semiconductor Nanostack for a Gate‐Tunable Ultrahigh‐Performance Stretchable Phototransistor

Abstract Despite being one of the most robust materials with intriguing optoelectronic properties, the practical use of single‐layer graphene (SLG) in soft‐electronic technologies is limited due to its poor native stretchability, low absorption coefficient, poor on/off ratio, etc. To circumvent these difficulties, here, a rippled gate‐tunable ultrahigh responsivity nanostack phototransistor composed of SLG, semiconductor‐nanoparticles (NPs), and metallic‐nanowires (NWs) embedded in an elastic film is proposed. The unique electronic conductivity of SLG and high absorption strength of semiconductor‐NPs produce an ultrahigh photocurrent gain. The metallic NWs serve as an excellent stretchable gate electrode. The ripple structured nanomaterials surmount their native stretchability, providing strength and electromechanical stability to the composite. Combining all these unique features, highly stretchable and ultrasensitive phototransistors are created, which can be stretched up to 30% with high repeatability maintaining a photoresponsivity, photocurrent gain, and detectivity of ≈10⁶ A W⁻¹, 10⁷, and 10¹³ Jones, respectively, which are comparable with the same class of rigid devices. In addition, the device can be turned‐off by applying a suitable gate voltage, which is very convenient for photonic circuits. Moreover, the study can be extended to many other 2D systems, and therefore paves a crucial step for designing high‐performance soft optoelectronic devices for practical applications.