Potential shielding by the surface water layer in Kelvin probe force microscopy
Potential shielding by the surface water layer in Kelvin probe force microscopy
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DOI：
10.1063/1.1455145
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发表时间：
2002-02-25
影响因子：
4
通讯作者：
Nakagiri, N
中科院分区：
文献类型：
--
作者：
Sugimura, H;Ishida, Y;Nakagiri, N
开尔文探针力显微镜（KFM）被施加到覆盖有2 nm厚的氧化层的硅pn结构的二维轮廓。当KFM成像在相对湿度大于50%的空气中进行时，p型和n型区域之间的表面电位对比取决于氧化物表面的疏水性。通过热退火降低氧化物层上的表面羟基的密度，p型和n型区域之间的电位差增加。虽然在水接触角几乎为0度的亲水性氧化物覆盖的样品上没有可检测到的对比度，但在水接触角约为80度的疏水性氧化物覆盖的样品上对比度增加到大于50 mV。然而，当在相对湿度小于0.6%的干燥氮气气氛中进行KFM成像时，即使在覆盖有亲水性氧化物层的样品上也可以获得约50 mV的清晰的电位对比度。由于其表面上的吸附水较少的样品表现出更大的潜在的对比度，对比度下降归因于吸附水层的屏蔽效应。(C)2002年美国物理学会。
Kelvin probe force microscopy (KFM) was applied to two-dimensional profiling of silicon pn-structures covered with a 2 nm-thick oxide layer. The surface potential contrast between the p-and n-type regions depended on the hydrophobicity of the oxide surface when KFM imaging was conducted in air with a relative humidity of more than 50%. By decreasing the density of surface hydroxyl groups on the oxide layer through thermal annealing, the potential contrast between the p- and n-type regions increased. While there was no detectable contrast on samples covered with hydrophilic oxide with a water contact angle of almost 0degrees, contrast increased to greater than 50 mV on the samples covered with hydrophobic oxide with a water contact angle of about 80degrees. However, when KFM imaging was conducted in a dry nitrogen atmosphere with relative humidity less than 0.6%, a clear potential contrast of about 50 mV could be acquired even on samples covered with the hydrophilic oxide layer. Since samples with less adsorbed water on their surface showed greater potential contrast, contrast degradation is attributed to a shielding effect of the adsorbed water layer. (C) 2002 American Institute of Physics.