高响应度氧化镓日盲紫外探测材料生长和器件研制

Ga2O3 is the only windbandgap conductive semiconductor material within UV-C band（200-280 nm）. Three main problems are obstacles to the rapid progress of Ga2O3 UV photodetector. The first one is the lack of suitable substrates. Only polycrystalline Ga2O3 films can be obtained. The second one is the doping control technique. The third one is relative with the above two: low responsibility, slow response, untunable response wavelength, and ambiguity about carrier transport mechanism. In this project, we will focus on wiping off thse problems. 1) Growth of high quality Ga2O3 film by introducing a flexible GaN buffer to transfer,absorb and reduce the strain in Ga2O3 because of the big lattice mistch between Ga2O3 and sapphire or quartz substrate. b) Growth of doping control Ga2O3 using Sn metal vapor as the presuror gas. c) fabrication of Ga2O3 photodetector with high responsibility. c.1) Transparent electrode works as electrode as well as part of the heterojunction. c.2) Undoped Ga2O3 layer is introduced to make MIS photodector and nin photodetector.

Ga2O3是唯一一个禁带宽度在UV-C波段的可掺杂的宽禁带半导体材料。但目前存在以下问题： 缺乏合适的异质外延衬底材料，氧化镓薄膜多是多晶、晶体质量差；缺乏可控的掺杂技术，p型掺杂困难；探测器响应度低、响应时间慢、响应范围难以调节，以及载流子传输机制尚不明确等。 本项目将研究1）引入氧化镓可协变缓冲层来释放、转移和隔离由于衬底和氧化镓之间大的晶格失配； 2）采用Sn金属蒸气源实现氧化镓的n型可控掺杂 3）采用透明电极既做氧化镓的引线电极，又和氧化镓形成异质结探测器。

本课题通过在蓝宝石、硅等衬底材料上用多种气相沉积的方法制备了高质量的氧化镓薄膜材料，研究了不同材料的可协变缓冲层对材料性质的影响。在实验中发现通过选择合适的衬底晶向，可以大幅度提高氧化镓薄膜的晶体质量。加入氧化亚铜缓冲层获得了高择优取向的氧化镓薄膜。.对氧化镓薄膜的光学性质和电学性质进行了测试，分析了氧空位在生成机制和对氧化镓电学性质的影响。.氧化镓的光学带隙为5.13 eV。氧空位是深能级，位于导带下约3.4 eV的位置。.使用不同的接触金属对氧化镓薄膜的接触电阻率进行了探索。进行了光电导型氧化镓日盲紫外探测器的制备。