六方BN单晶材料的HVPE生长研究

Hexagonal boron nitride (h-BN) is a important substrate material for the fabrication of graphene-based electronic devices and basic material for the fabrication of deep ultraviolet optoelectronic devices. However, the fabrication of high-quality large-size h-BN crystal is still very difficult due to the high melting temperature (about 2800 ℃) and decompression pressure of h-BN. The proposed project will use hydride vapor phase epitaxy（HVPE）to grow single crystal h-BN by a special processing technologies, which can provide high growth rate and be suitable for large-size single crystal growth. Basing on the above ideas and using the association of experimental result and theoretical simulation, we will study the growth kinetics of h-BN thick films and establish of growth kinetics model for HVPE growth of h-BN. In addition, the project will also carry out an in-depth study of defects control technology in h-BN, explore an effective way to reduce the defect density, master key technology for the growth of hexagonal h-BN single crystal materials, to obtain a high quality and large-size h-BN single crystal thick-film materials for giving a great support for the development of new generation of graphene-based electronic devices and h-BN based deep ultraviolet optoelectronic devices of our country.

六方氮化硼(h-BN)单晶是制备高性能石墨烯基电子器件的重要衬底材料，也是制备深紫外发光器件的基础材料。由于h-BN晶体有极高的熔点温度（约2800 ℃）和分解压，大尺寸高质量的h-BN晶体的获得至今仍是个难题。本项目拟利用氢化物气相外延（HVPE）法具备的高生长速率和适合大尺寸氮化物单晶生长的优势，采用特殊工艺技术生长h-BN单晶材料。我们将围绕上述思路，理论模拟与实验相结合，研究h-BN厚膜制备过程中的生长动力学过程，建立h-BN的HVPE生长动力学模型；深入研究h-BN中的缺陷控制技术，探究降低缺陷密度的有效途径；掌握h-BN单晶材料生长的关键技术，获得较高质量和较大尺寸的h-BN单晶厚膜材料，为我国发展新一代石墨烯基电子器件、h-BN基深紫外光电器件奠定基础。

六方氮化硼(h-BN)单晶是制备高性能石墨烯基电子器件的重要衬底材料，也是制备深紫外发光器件的基础材料。由于h-BN晶体有极高的熔点温度（约2800 ℃）和分解压，大尺寸高质量的h-BN晶体的获得至今仍是个难题。本项目利用氢化物气相外延（HVPE）法在石墨衬底、蓝宝石衬底上生长了h-BN厚膜材料（十几微米到几百微米不等），并实现与衬底的自分离。结构表征表明，我们获得的h-BN材料的是沿着[0001]方向层状生长，但（0001）平面内存在着大量晶界，晶界是h-BN材料的主要缺陷。通过对生长工艺的探索，我们发现，在大氨气流量（高V/III）下可以获得半透明的h-BN厚膜，光学带隙大约在3.10 eV -3.35 eV之间，XRD（0002）面扫描的半高宽1.0度~1.7度之间。虽然h-BN的晶体质量还有待提高，但是通过本项目的研究，我们进一步完善了HVPE生长h-BN的设备，探索了2英寸半透明的h-BN厚膜的生长工艺，为进一步或获得更高质量和更大尺寸的h-BN单晶材料奠定了基础。