Comparison of wet chemical treatment and Ar-ion sputtering for GaInP2(100) surface preparation
Comparison of wet chemical treatment and Ar-ion sputtering for GaInP2(100) surface preparation
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DOI：
10.1016/j.mssp.2016.05.005
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发表时间：
2016-08
影响因子：
4.1
通讯作者：
M. Lebedev;N. Kalyuzhnyy;S. Mintairov;W. Calvet;B. Kaiser;W. Jaegermann
中科院分区：
文献类型：
--
作者：
M. Lebedev;N. Kalyuzhnyy;S. Mintairov;W. Calvet;B. Kaiser;W. Jaegermann
用同步辐射激发的高分辨表面灵敏光电子能谱研究了自然氧化物覆盖的p-GaInP_2（100）表面与1 M HCl和40-48%（NH_4）_2S水溶液的相互作用。硫化铵水溶液比HCl水溶液更有效地蚀刻天然氧化物层。在用任何溶液蚀刻之后，磷酸镓完全消失，并且表面仍然分别覆盖有仅少量的铟磷酸盐和氢氧化物、镓低氧化物以及镓和铟的氯化物或硫化物。在湿法蚀刻之后，保留约0.5eV的带弯曲，如对于未处理的表面所观察到的。Ar离子溅射的自然氧化物覆盖的p-GaInP 2（100）表面和随后的退火的结果在Ga/In的原子比的强烈增加，在减少的表面能带弯曲，并在增加的表面功函数。由于Ar离子溅射和随后的退火导致p-GaInP_2化合物的近表面层的相当大的变形，因此不能认为它是制备良好限定的p-GaInP_2（100）表面的令人满意的方法。另一方面，即使在长时间暴露于HCl水溶液（30分钟）之后，用HCl水溶液蚀刻的p-GaInP 2（100）表面的化学组成保持稳定，这对于太阳能水裂解电池的开发可能是重要的。
The interaction of the native oxide covered p-GaInP2(100) surface with aqueous 1 M HCl and 40–48% (NH4)2S solutions is studied by high-resolution surface-sensitive photoemission spectroscopy excited by synchrotron radiation. The aqueous ammonium sulfide solution is more efficient in etching the native oxide layer than the aqueous HCl solution. After etching with any of the solutions, the gallium phosphates disappear completely and the surface remains covered with only a little amount of indium phosphates and hydroxides, gallium suboxides, as well as gallium and indium chlorides or sulfides, respectively. After wet etching a band bending of about 0.5 eV remains, as it is observed for the untreated surface. Ar ion sputtering of the native oxide covered p-GaInP2(100) surface and subsequent annealing results in a strong increase of the Ga/In atomic ratio, in a decrease in the surface band bending, and in an increase in the surface work function. Since the Ar-ion sputtering and subsequent annealing results in considerable distortion of the near-surface layer of the p-GaInP2compound, it cannot be considered as a satisfactory method for the preparation of a well-defined p-GaInP2(100) surface. On the other hand, even after prolonged exposure (30 min) to aqueous HCl solution the chemical composition of the p-GaInP2(100) surface etched with aqueous HCl solution remains stable, which can be of importance for the development of solar water splitting cells.