Rathod Shasvat, Snowdon Monika, Jones Joshua, Zhang Kaiping, Peng Peng
Centre for Advanced Materials Joining, Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.
ACS Appl Mater Interfaces. 2023 Dec 4. doi: 10.1021/acsami.3c11552.
Multifunctional three-dimensional heterostructures for flexible electronics have gained significant attention due to their distinctive structural formability and superior electronic and optoelectronic properties. Nevertheless, conventional fabrication techniques have yet to be optimized for flexible substrates. In this study, a straightforward fiber laser direct writing (FLDW) process is demonstrated for the simultaneous fabrication of diodes (PN junctions) and bipolar junction transistors (BJTs) on flexible polyimide substrates, which is realized through the deposition of multifunctional p- or n-type copper oxide films (CuO) and p- or n-type porous laser-reduced graphene oxide films (LrGO) using fiber laser ablation and deposition. The presence of both p- and n-type semiconductor films is confirmed through material characterization. The fabricated PN junctions exhibit reasonable diode rectification ratios, ranging from 20 to 220, and perform reliably under numerous operating conditions such as light-dark illumination and elevated temperatures. Furthermore, - curve analysis indicates that the current gain and electrical performance of printed negative-positive-negative (NPN) (or positive-negative-positive, PNP) BJTs can be tailored by adjusting the laser energy density of the FLDW process and the base gap width of the BJTs. As a proof of concept, the FLDW process is successfully employed to deposit both NPN (or PNP) BJTs composed of LrGO/CuO heterostructures with controlled current gains. Its ease of operation, versatility, and cost-effectiveness make FLDW promising for large-scale flexible electronics fabrication.
用于柔性电子器件的多功能三维异质结构因其独特的结构可成型性以及优异的电子和光电性能而备受关注。然而，传统的制造技术尚未针对柔性基板进行优化。在本研究中，展示了一种直接的光纤激光直写（FLDW）工艺，用于在柔性聚酰亚胺基板上同时制造二极管（PN结）和双极结型晶体管（BJT），这是通过使用光纤激光烧蚀和沉积来沉积多功能p型或n型氧化铜薄膜（CuO）以及p型或n型多孔激光还原氧化石墨烯薄膜（LrGO）来实现的。通过材料表征证实了p型和n型半导体薄膜的存在。所制造的PN结表现出合理的二极管整流比，范围为20至220，并且在诸如明暗光照和高温等多种工作条件下都能可靠运行。此外， - 曲线分析表明，通过调整FLDW工艺的激光能量密度和BJT的基极间隙宽度，可以调整印刷的NPN（或PNP）BJT的电流增益和电气性能。作为概念验证，FLDW工艺成功用于沉积由具有可控电流增益的LrGO/CuO异质结构组成的NPN（或PNP）BJT。其操作简便、通用性强且成本效益高，使得FLDW在大规模柔性电子制造方面具有广阔前景。
