Template‐Guided C8‐BTBT/MAPbBr3/C8‐BTBT Heterostructures for Broadband Bipolar Phototransistors

Abstract Bipolar junction transistor (BJT) has had an unprecedented impact on the electronic industry and helped to usher in the digital revolution prominently. However, the critical part of BJT, p–n junction, is formed by carefully incorporating substitutional impurities in traditional bulk semiconductors and it is difficult to implement in nanostructured device. In this work, a floating‐base BJT device is demonstrated by growing C8‐BTBT/MAPbBr 3 /C8‐BTBT PNP heterostructure in liquid phase. Growth of two semiconductor microwires into a crisscross heterojunction is achieved through template‐guided printing and antisolvent crystallization method. The proof‐of‐concept phototransistor demonstrates broadband light absorption from ultraviolet (UV) to visible spectral region, which exhibits enhanced photoresponsivities of 1.28 A W –1 to UV and 0.425 A W –1 to visible light, respectively. In addition, the improved photoelectric amplification behavior of C8‐BTBT/MAPbBr 3 /C8‐BTBT phototransistor is observed by comparing with the performance of C8‐BTBT/MAPbBr 3 two‐component photodiode. The maximal gain can reach up to ≈600 and can be maintained ≥200 at the positive bias. The device provides new attractive prospects in the investigation of integrated circuits based on micro‐structured semiconductors.