The Time Dependent Red Shift Phenomenon of Visible Electroluminescence of Porous Silicon
- 1998年第4卷 
本文着重研究了多孔硅（ＰｏｒｏｕｓＳｉｌｉｃｏｎ，简称ＰＳ）在阴极偏压下过硫酸铵溶液中电压调制的电致发光（Ｅｌｅｃｔｒｏｌｕｍｉｎｅｓｃｅｎｃｅ，简称ＥＬ）现象．发现在定电压下，随极化时间的增长电致发光强度减小并伴随着光谱红移现象．通过红外、拉曼、ＡＦＭ及光电化学等手段对电致发光的淬灭机制进行了研究，结果表明，在电致发光过程中强氧化剂向多孔硅注入空穴使ＰＳ表面氧化，导致小粒径的硅晶逐渐被剥落，造成光谱高能部分首先淬灭并出现随时间变化的电致发光红移现象．这些结果支持量子限制效应在多孔硅液相电致发光中起着重要作用The electroluminescence (EL) of ntype porous silicon (PS) in a persulphate solution under cathodic polarization was studied. A significant red shift in the luminescence spectra with the increase of polarization time, as well as a blue shift with the increase of cathodic polarization, have been found. FTIR, MicroRaman, AFM and photoelectrochemical techniques have been used to investigate the structure of PS before and after the electroluminescence emission. All these results show that the surface of PS has been oxidized by the persulphate during the EL emission, and accompanied by the stripping of small silicon nanocrystallite, which leades to the red shift of the electroluminescence spectrum. Both of the voltagetunable electroluminescence and the timedependent red shift of the EL spectra support that quantum confinement effect (QCE) plays an important role in the electroluminescence in liquid contact.