超宽禁带二维半导体材料与器件研究进展

Research progress of ultra-wide bandgap two-dimensional semiconductor materials and devices

超宽禁带二维半导体作为二维材料研究领域的前沿之一,在紧跟第三、四代半导体朝着大带隙、大功率方向发展的同时,也为集成电路往小体积、高集成度方向的探索提供了思路.根据晶体堆积是否为范德华层状结构,超宽禁带二维半导体在材料层面的研究内容一方面是将已有的或成熟的非层状材料通过各种限制手段将第三维度压制在纳米量级,另一方面则是探索新型的范德华层状材料通过生长或剥离的方式得到其单层或少层结构.从器件层面看,超宽禁带二维半导体无论是以独立形式还是两两组合叠成异质结,形成的器件大多都以探测紫外波段的电磁辐射为目的,进一步可以做成包括成像系统、数字通讯等在内的光学传感器.若是辅助以柔性衬底,那么二维材料将发挥天然的可弯折优势,被广泛应用到柔性场效应晶体管、柔性紫外探测器、显示器等可穿戴电子器件中.而当材料有对外界刺激(如光照)表现出“记忆”特性时,说明可以将材料用于类神经突触传感或神经网络学习.此外,超宽禁带二维半导体中具有超大带隙的部分材料是极具潜力的电介质,它们往往拥有远比氧化硅大的介电常数与击穿电压,在减薄器件体积的同时也优化了器件的性能.最后,少数超宽禁带二维半导体是许多材料制备过程中的衬底,它们的简单易得和原子级洁净的表面为各种新材料的诞生提供了温床,是二维材料领域的重要基石.

As one of the frontiers in the field of two-dimensional materials research,ultra-wide bandgap two-dimensional(UWBG 2D)semiconductors,while following the development of the third and fourth generation semiconductors in the direction of large bandgap and high power,provide ideas for the exploration of integrated circuits towards small volume and high integration.According to whether the crystal stacking is a van der Waals layered structure,from the perspective of material,the research content of UWBG 2D semiconductors is aimed at obtaining ultra-thin film of the existed and mature nonlayered materials through versatile methods and exploring novel van der Waals layered materials to get the single layer or few layers by direct growth or exfoliation.From the perspective of device,the UWBG 2D semiconductors are mostly formed to detect electromagnetic waves in the ultraviolet solar-blind region,whether they are in an independent form or stacked in pairs to form a heterojunction.Furthermore,they can be completed with additional circuits and devices to become imaging system,digital communication equipment or other optical sensors.If assisted by a flexible substrate,2D materials will take advantage of their natural bendability and be widely used in wearable electronic devices such as flexible field-effect transistors,flexible UV detectors,and displays.When the material has the property of“memory”to external stimuli(such as light),it means that the material can be used for neural-like synaptic sensing or neural network learning after training.In addition,some materials with extremely large bandgaps in UWBG 2D semiconductors are potential dielectrics.They often have a much larger dielectric constant and breakdown voltage than silicon dioxide,which can reduce the size of the device while improving the performance.Finally,a few UWBG 2D semiconductors are naturally good substrates in the preparation of many materials due to their easy availability and atomically clean surfaces,which provide the breeding ground for the birth of a variety of new materials,making them critical cornerstones in the field of 2D material.