多孔硅上贵金属的浸入沉积

将多孔硅浸入含贵金属盐的HF溶液20 s, 制备了Ag, Au, Pd和Pt的沉积层. AFM形貌显示, 这4种贵金属都能在多孔硅上直接沉积, 但Pt的沉积量比其他3种少. SEM图及能谱(Energy dispersive X-ray spectrometer, EDS)分析显示, 沉积层优先生长在孔边上, 孔边上的沉积量约是孔底的4.6倍. 电化学方法分析显示, Pd和Pt, Ag和Au的沉积层分别具有类似的开路电位和交流阻抗特性, 其中Pd层的溶出电流比其他3种大1个数量级, 而阻抗比其他小1个数量级, 说明Pd层与硅基底的结合程度好, 结合界面导电性好.

mmersion Deposition of Noble Metal on Porous Silicon

The deposition layers of Ag, Au, Pd and Pt on porous silicon (PS) were prepared by the immersion deposition. The deposition bath was 0.5 mol?L^－1 HF aqueous solution containing noble metal salts and the deposition time was 20 s. Atomic force microscope morphologies showed that all the four noble metals could deposit on the PS, but the amount of Pt deposits was smaller than those of the others. Scanning electron microscope images and energy dispersive X-ray spectrometer analysis demonstrated that the deposition of noble metal occurred preferentially on the borders of pores, and the amount of noble metal depositing on the borders was 4.6 times as large as that on the bottoms. Electrochemical techniques presented that Pd and Pt, Ag and Au, respectively possessed similar properties in open circuit potential and A.C. impedance. Compared with others, the Pd deposit had distinct characters. Its oxidation current is one order of magnitude bigger than those of the others and its impedance is smaller than those of the others by one order of magnitude. This showed that the conductivity of Pd deposit/silicon heterojunction was higher than those of others due to the better adhesion of Pd on silicon substrate.