Gate Tunable Symmetric Bipolar Junction Transistor Fabricated via Femtosecond Laser Processing

摘要： Two-dimensional (2D) bipolar junction transistor (BJT) with van der Waals heterostructures plays an important role in the development of future nanoelectronics. Herein, a convenient method is introduced for fabricating a symmetric bipolar junction transistor (SBJT) constructed with black phosphorus and MoS2 with femtosecond laser processing. This SBJT exhibits good bidirectional current amplification thanks to its symmetric structure. Next, we place a top gate on one side of the SBJT to change the difference in the major carrier concentration between the emitter and collector in order to further investigate the effect of electrostatic doping on the device’s performance. The SBJT can also act as a gate tunable phototransistor with good photodetectivity and photocurrent gain of β ~ 21. Scanning photocurrent images are used to determine the mechanism governing photocurrent amplification in the phototransistor. These results promote the development of the applications of multifunctional nanoelectronics based on 2D materials.