Chloride Multisource Epitaxial Growth of Chalcopyrite Semiconductors and Control of Their Electrical Properties

提出了一种新的黄铜矿半导体外延生长技术，即氯化物多源外延生长技术。以一氯化铜(CuCl2)、金属镓(Ga)和硒(Se)为原料，在GaAs(100)衬底上生长了CuGaSe_2的c轴外延层。通过控制薄膜的化学计量比和非本征掺杂来控制生长的薄膜的电学性能，未掺杂的薄膜具有p型电导率，其电导率范围为10^~(-2)~10^3s，这取决于Se/(CuCl+Ga)和CuCL/Ga的供应比。高的Se/(CuCl+Ga)供应比降低了电导率，因为过量的Se起到了补偿施主的作用。较低的CuCL/Ga供应比增加了电导率，因为铜空位形成了受主能级。通过分析载流子浓度对温度的依赖关系，确定受主电离能为180 meV。掺锌层为p型电导，Sigma=3*10^&lt；-2&gt；-5*10^2S。研究了源供应比，即Se/(CuCL+Ga)和CuCL/Ga供应比对电导率的影响，发现锌处于Ga位，形成130 meV的受主能级。通过在铜位引入锌原子来实现n型导电的尝试是不成功的，氮气的掺杂是通过活性氮掺杂技术来实现的。在N掺杂样品中观察到40-50mdv的浅受主能级。

A novel epitaxial growth technique of chalcopyrite semiconductors has been developed, that is chloride multi source epitaxial growth. The c-axis epitaxial layrs of CuGaSe_2 were grown on GaAS (100) substrates using copper monochloride (CuCl), metallic gallium (Ga) and selenium (Se) as source materials. Electrical properties of grown layrs were controlled both by controlling the stoichimetry of the layrs and by extrinsic doping.Undoped layrs were of p-type conductivity, and there conductivities ranged from 10^<-2>S to 10^3S depending on Se/(CuCl+Ga) and CuCl/Ga supply ratios. High Se/(CuCl+Ga) supply ratios decreased the conductivities, because excess Se acted as compensating donors. Low CuCl/Ga supply ratios increased the conductivities, because Cu vacancies formed acceptor levels. The ionization energy of the acceptor was determined to be 180meV by analyzing temperature dependence of carrier concentrations.Zn-doped layrs were of p-type conduction with sigma=3*10^<-2>-5*10^2S.The effects of source supply ratios, that is, Se/(CuCl+Ga) and CuCl/Ga supply ratios on the electrical conductivity were studied, and Zn was found to be on the Ga site and to make a 130meV acceptor level. The attempt to realize n-type conduction by introducing Zn atoms into the Cu sites was not successful.Nitrogen was doped by the technique of active nitrogen doping. Shallow acceptor levels of 40-50mdv activation energies were observed in N doped samles.