金属辅助化学腐蚀法制备硅纳米线的形貌及发光性能

Morphology and photoluminescence properties of silicon nanowires prepared by metal-assisted chemical etching

摘要:

金属辅助化学腐蚀(metal-assisted chemical etching,MACE) 法制备的硅纳米线(silicon nanowires,SiNWs)具有光致发光(photoluminescence,PL) 性能,但制备条件对SiNWs的结构和发光性能有较大影响。为获得结构形貌和发光性能较佳的SiNWs,本文对腐蚀液中H₂O₂的浓度、腐蚀液温度、腐蚀时间等制备参数进行了优化。研究表明,腐蚀液中H₂O₂浓度为0.50 mol/L,温度为25 ℃条件下腐蚀速率适中,形成的SiNWs最均匀规整,其PL性能最好。随着腐蚀时间增加,SiNWs长度和表面氧化物呈增长趋势,SiNWs直径在100 nm左右。橙红色PL谱被认为是硅纳米晶体的量子限制效应引起,随着腐蚀时间增长,633 nm和699 nm的两个主发光峰位皆发生蓝移。腐蚀4 min的SiNW结构和长度适中,其发光强度最强,比腐蚀12 min样品光强大了一个数量级。该法制备的SiNWs在基于硅纳米结构光电器件的制备中具有重要的应用潜力。

Abstract:

Silicon nanowires (SiNWs) prepared by metal-assisted chemical etching (MACE) method have photoluminescence (PL) properties.However,the preparation conditions have great influence on the structure and luminescence properties of SiNWs.To obtain SiNWs with better structural morphology and luminescence properties,the H₂O2 concentration,etching temperature and etching time were optimized.The results show that when the concentration of H₂O₂ in the etching solution is 0.5 mol/L and the temperature is 25 ℃,the etching rate is moderate,the SiNWs have the most uniform and regular structure,and the PL performance is the best.With the increase of etching time,the length of SiNWs and surface oxides show an increasing trend,and the diameter of SiNWs is about 100 nm.The orange-red PL spectrum is believed to be caused by the quantum confinement effect of silicon nanocrystals.With the increase of etching time,the two main luminescence peaks at 633 nm and 699 nm are blue shifted.The SiNWs etched for 4 min have a moderate structure and length,and the luminescence intensity is the strongest,which is an order of magnitude stronger than that etched for 12 min.SiNWs prepared by this method have important application potential in the fabrication of silicon nanostructured based optoelectronic devices.