硫钝化可提高GaSb表面光学性质

由于锑化镓（GaSb）表面存在着大量的氧化物及悬挂键，使得材料具有较高的表面态密度，这将导致GaSb费米能级钉扎，严重限制了其器件的应用和发展。同时，这些氧化物及悬挂键将构成非辐射复合中心，影响表面发光。本文通过酸性饱和S2Cl2溶液（最优钝化时间为5s）对n型GaSb进行表面钝化后发现：该溶液钝化可有效减少GaSb表面的氧化物及悬挂键，改善光学性质。从理论上分析了S2Cl2溶液的钝化机理，同时利用PL、PL mapping、XPS及AFM等测试手段验证了该分析的准确性。另外，与常规的碱性（NH4）2S溶液（最优钝化时间为180s）对比，发现经S2Cl2钝化后样品的单点发光强度是（NH4）2S溶液处理过的样品1.5倍，是未处理样品的25倍。但S2Cl2溶液中含有较高的硫浓度，操作时不宜控制，极易腐蚀GaSb表面，钝化后样品表面有大量单质S析出，其发光均匀性及表面平整度不如（NH4）2S溶液。

The Improvement of Gallium Antimonide Surface by Sulphur Passivation

The dichloride disulfide (S2Cl2) is employed to passivate the GaSb surface. The surface optical and chemical properties of GaSb surface before and after passivation are investigated by using X-ray Photoelectron Spectroscopy (XPS),Photoluminescence (PL),Photoluminescence Mapping (PL mapping) and Atomic Force Microscope (AFM). It is proved S2Cl2 solution can effectively remove oxides and dangling bonds on GaSb surface,lower the density of surface states,reduce the nonradiatives recombination centers,improve the optical properties. In addition,compared to the regular alkaline (NH4)2S,photoluminescence intensity is improved 1.5 times,stronger 25 times as untreated one. However,lumi-nescence homogeneity and surface morphology of gallium antimonide surfaces passivated by S2Cl2 are much more worse.