Department of Engineering Physics, Centre for Emerging Device Technologies, McMaster University, Hamilton, ON L8S 4L7, Canada.
Nanotechnology. 2012 Aug 10;23(31):315703. doi: 10.1088/0957-4484/23/31/315703. Epub 2012 Jul 13.
The effect of ammonium polysulfide solution, (NH₄)₂S(x), on the surface passivation of p-doped InP nanowires (NWs) was investigated by micro-photoluminescence. An improvement in photoluminescence (PL) intensity from individual NWs upon passivation was used to optimize the passivation procedure using different solvents, sulfur concentrations and durations of passivation. The optimized passivation procedure gave an average of 24 times improvement in peak PL intensity. A numerical model is presented to explain the PL improvement upon passivation in terms of a reduction in surface trap density by two orders of magnitude from 10¹² to 10¹⁰ cm⁻², corresponding to a change in surface recombination velocity from 10⁶ to 10⁴ cm s⁻¹. The diameter dependence of the PL intensity is investigated and explained by the model. The PL intensity from passivated nanowires decreased to its initial (pre-passivation) value over a period of seven days in ambient air, indicating that the S passivation was unstable.
采用微光致发光法研究了多硫化铵溶液((NH₄)₂S(x))对 p 型掺杂的 InP 纳米线(nw)表面钝化的影响。通过优化不同溶剂、硫浓度和钝化时间的钝化程序，利用单个 NWs 的光致发光(PL)强度的提高来优化钝化程序。优化后的钝化程序使峰值 PL 强度平均提高了 24 倍。提出了一个数值模型，根据表面陷阱密度降低了两个数量级(从 10¹²到 10¹⁰ cm⁻²)，表面复合速率从 10⁶到 10⁴ cm s⁻¹，解释了 PL 增强的原因。通过该模型研究了 PL 强度与直径的关系，并对其进行了解释。在环境空气中，钝化后的纳米线的 PL 强度在七天内下降到初始(预钝化)值，表明 S 钝化是不稳定的。
