掺杂和未掺杂氧化锌薄膜的拉曼光谱

利用拉曼光谱分别对不同衬底上,未掺杂和掺杂以及掺杂浓度不同的ZnO薄膜进行了系统的分析研究。其中ZnO薄膜均由溶胶-凝胶法制得,掺杂源为LiCl。测得的拉曼光谱显示,Pt/Ti/SiO2/Si衬底上生长的ZnO薄膜的拉曼特征峰(437cm-1)的强度明显高于SiO2/Si衬底上ZnO薄膜的拉曼特征峰的强度,说明Pt/Ti/SiO2/Si衬底上ZnO的晶化程度比SiO2/Si上ZnO的晶化程度高;但ZnO拉曼特征峰的位置和半高宽并没有发生变化,说明两种衬底上ZnO薄膜中应力大小没有发生变化。掺Li+后,580cm-1处的峰位向高频方向移动,且掺杂浓度越大频移量越大,说明掺杂已经在不同程度上引起了ZnO晶体中自由载流子浓度的变化。此外,还分析了掺Li+未在很大程度上引起ZnO晶格畸变的原因。

Raman Spectra of Undoped and Doped ZnO Thin Films

In this paper,the structure characteristics and the phase composition of undoped ZnO thin films and doped ZnO thin films with LiCl are studied with Raman spectroscopy.All the ZnO thin films are prepared by sol-gel spin-coating technique and two different kinds of substrates are used in the preparation of ZnO thin films,Pt/Ti/SiO_2/Si and SiO_2/Si.The Raman spectrum show that the intensity of E_2 peaks(437cm~(-1)) of ZnO thin film on the former substrate is significant stronger than that of ZnO thin film on the latter one,which indicates that the crystallinity content of the ZnO on the former substrate is higher than that of on the latter one.The result is also shown that the positions and full width at half maximum of E_2 peaks are the same,which indicates that the tensile residual or stress in ZnO on the two kinds of substrates is the same.For the doped ZnO thin films,the A_1(LO) mode(580cm~(-1)) frequency shifts to higher wavenumbers.And the shiftline increases with the doping concentration,which indicates that doping can change the free carrier concentration in the ZnO thin films in various degrees.Furthermore,we found the phenomenon which doping did not cause intensive lattice aberration and analyzed the reason.