介质衬底上h-BN二维原子晶体的直接生长及其器件应用

Two-dimensional (2D) hexagonal boron nitride (h-BN) has attracted considerable attention due to its unique structure, novel properties and potential applications. Transition metal substrates are usually used for the growth of 2D h-BN layers and a complex transfer process is often required. Therefore, the direct growth of 2D h-BN on dielectric substrates is extremely important for its practical application. However, due to the lack of catalytic activity of the dielectric substrates, it is difficult to nucleate h-BN on dielectric substrates and its crystalline quality is poor. In the present project, we propose to synthesis 2D h-BN on commonly used c-sapphire and SiO2/Si substrate by ion beam sputtering deposition (IBSD) technique. On the one hand, to promote the nucleation of h-BN, the dielectric substrates are bombarded by the in situ N+ ion beam, which is called as surface nitridation. On the other hand, the h-BN target is sputtered by an N+ ion beam to avoid the deficiency of N atoms, improving the quality of h-BN layer. The goal of the present project is synthesizing high quality and wafer-scale 2D h-BN layer on dielectric substrates, and elucidating the growth mechanism of h-BN on dielectric substrates. Based on the high quality h-BN film, we will fabricate the UV photodetectors and field effect transistor to examine the properties of h-BN. The findings of this project will offer a promising approach toward both the basic research and electronic applications of 2D h-BN.

近年来，六方氮化硼（h-BN）二维原子晶体以其独特的结构、优异的性质备受关注。多数h-BN生长在金属衬底上，表征和应用时通常涉及复杂的转移过程。介质衬底上直接生长h-BN则可以避免低效繁琐的转移过程，然而，由于介质衬底缺乏催化活性，导致在其表面上h-BN成核困难、结晶质量有限。. 本项目中，我们拟采用离子束溅射沉积技术，在蓝宝石和SiO2/Si等常用介质衬底上制备h-BN二维原子晶体。通过荷能离子束对衬底表面进行氮化处理，促进h-BN成核；利用氮离子束溅射沉积h-BN，避免生长过程中氮的缺失，提高h-BN结晶质量。通过该项目的实施，我们期望实现介质衬底上高质量、晶圆尺寸h-BN二维原子晶体的可控生长，探明h-BN在介质衬底上的生长机理，并探索其作为栅介质和深紫外光电材料的应用，验证材料性能。因此，该项目的实施对h-BN二维原子晶体的基础研究和光电子学应用都有着十分重要的意义。

六方氮化硼（h-BN）以其独特的结构、优异的光电性质近年来备受关注。多数h-BN生长在金属衬底上，表征和应用时通常涉及复杂的转移过程。介质衬底上直接生长h-BN则可以避免低效繁琐的转移过程，对于大面积光电子学应用具有重要意义。实现介质衬底上高质量h-BN二维原子晶体的直接生长及器件应用是本项目的重要目标。本项目通过衬底表面原位氮化处理结合氮离子束溅射，在c面蓝宝石衬底上直接生长得到结构有序、具有理想化学计量比的h-BN薄膜；在腔室内引入氨气作为生长源，实现了较低温度下高结晶质量的h-BN薄膜的制备；基于介质衬底上直接生长的h-BN薄膜研制了光导型深紫外探测器，相比于转移法制备的器件，直接生长的h-BN器件表现出更好的光电响应特性，同时通过碳掺杂进一步调控载流子输运，使得器件性能达到国际领先水平。此外，在本项目的基础上开展了部分拓展研究，利用脉冲激光沉积技术，在c面蓝宝石衬底上实现了大面积多层h-BN单晶薄膜的直接生长，以及在超宽禁带氧化镓衬底上生长了h-BN，为h-BN的应用奠定了基础。总之，本项目研究突破了介质衬底上生长高质量、晶圆级h-BN的技术壁垒，不仅对于满足深紫外光电探测、关键性衬底等应用需求具有重要科学意义，也为超宽禁带半导体材料发展与应用提供了一定的支撑。