Effects of (NH4)2Sx treatment on indium nitride surfaces
Effects of (NH4)2Sx treatment on indium nitride surfaces
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DOI：
10.1063/1.3318685
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发表时间：
2010-02-15
影响因子：
3.2
通讯作者：
Yeh, J. Andrew
中科院分区：
文献类型：
--
作者：
Chang, Yuh-Hwa;Lu, Yen-Sheng;Yeh, J. Andrew
采用霍尔效应测量、x射线光电子能谱（XPS）和扫描开尔文探针显微镜（SKPM）对硫化铵[(NH4)(2)S-x]处理的氮化铟（InN）表面进行了研究。经（NH4）(2)S-x处理后，片材载流子密度降低（0.8-0.9）x10(13) cm(-2)，导致片材电阻增加。通过数值求解泊松方程，推导出表面带弯曲的相关上移为0.3 eV。XPS表征表明，经过（NH4）(2)S-x处理的InN表面有效抑制了天然氧化物的形成，形成了与表面In原子共价键合的硫层。该表面in - s偶极子层导致电子亲和力增加，从而导致XPS观察到的较低的表面弯曲位移（0.2 eV）。电子亲和力增加了0.1 eV，这与SKPM的结果一致。因此，（NH4）(2)S-x处理已被证明是减少InN表面带弯曲的有效方法。
Indium nitride (InN) surfaces treated with ammonium sulfide [(NH4)(2)S-x] are investigated using Hall effect measurement, x-ray photoelectron spectroscopy (XPS), and scanning Kelvin probe microscopy (SKPM). Upon the (NH4)(2)S-x treatment, the sheet carrier density is reduced by (0.8-0.9)x10(13) cm(-2), leading to an increase in the sheet resistance. By numerically solving the Poisson's equation, the associated upward shift of the surface band bending is derived to be 0.3 eV. XPS characterization shows, on the (NH4)(2)S-x treated InN surface, the formation of native oxide is effectively suppressed and a covalently bonded sulfur layer with surface In atoms is formed. This surface In-S dipole layer results in an increase in the electron affinity, thus giving rise to a lower surface bending shift (0.2 eV) observed in XPS. The electron affinity increase of 0.1 eV can be deduced, which is consistent with the result obtained by SKPM. Thus, the (NH4)(2)S-x treatment has been demonstrated to be an effective method for reducing the surface band bending for InN.