双极型晶体管作为重要的半导体器件之一，它以双p-n结、窄基区为特征，以高放大倍数、高速响应为特点，广泛应用在微电子器件中。本项目利用二维原子晶体材料独特性能，以二硫化钼、二硒化钨等为对象，在制备垂直二维叠层结构范德华双极晶体管的基础上开展电学及其功能电路研究。在器件结构制备方面，通过二维材料的精确组装，实现范德华异质结的可控制备、范德华异质结阵列的高质量制备，为二维电子器件的集成和功能化提供基础。在电学研究方面，系统研究范德华双极晶体管对交流小信号的频率响应，建立二维尺度下频率响应物理模型，分析放大机制。在功能电路研究方面，通过两个或多个范德华双极晶体管电互连组成功能电路，分别研究范德华达林顿晶体管、范德华双极晶体管阵列的二级和多级放大特性，实现功能电路的可控放大。为二维尺度下高工作频率、高放大倍数、低功耗、易于集成、具有多级放大功能的新型双极晶体管的研制提供研究基础。

Bipolar junction transistors (BJT), as one of the most important semiconductor device, is characterized by dual p-n junction with narrow base region as well as high current gain and high-speed response, which is widely used in the field of modern microelectronic devices. This proposal starts with the motivation towards the development of new semiconductor devices by utilizing the unique properties of two dimensional atomic crystal (2D) materials, with special interest in constructing vertically stacked van der Waals bipolar junction transistors (V2D-BJT) and studying their electrical and and function circuit properties. Firstly, for the device structure preparation, we are committed to the controllable fabrication of van der Waals heterojunction as well as high-quality van der Waals heterostructure arrays through precisely assemble of the two-dimensional materials. This may provides basis for the integration and functionalization of 2D electronic devices. Then, we will focus on studying the electrical properties of the V2D-BJT. Through systematically studying the frequency response of the V2D-BJT to small alternating current (AC) signals, we will establish a 2D frequency response physical mode and analyze the corresponding amplification mechanism. In terms of the functional circuit characteristics, two or more van der Waals bipolar junction transistors are electrically interconnected to form a functional circuit. We will separately study the two-stage or multi-stage amplification performances of the van der Waals darlinton transistors and V2D-BJT arrays to realize the controllable amplification of the functional circuit. These studies may provide solutions for the realization of novel 2D bipolar junction transistors with higher operating frequency, lower power consumption, higher integration, controllable current gain and multi-stage amplification.