摘要
实验研究表明,SnO_2薄膜经过退火处理后其光致发光谱有明显的变化。在氧和氮两种不同气氛中进行热处理,其变化也有差异。这种变化主要是由于SnO_2膜中氧空位和自由载流于浓度变化所致。
Thin films of SnO_2 can be prepared in a highly conductive form with the important properly of being highly transparent in the visible and near-IR regions of the solar spectrum. Potential applications of the thin film are coatings in heat minor systems as well as in solat cell technology. In this paper, we report the effect of annealing temperature on the photoluminescence of SnO2 films. Experimental samples were made by the spraying method that involves the decomposition at high temperature ( around 500℃) of a mineral compound such as SnCl4.5H2O dissolved in a solution of water and alcohol. Water is used here as an oxidizing agent.Experimental results show that the annealing process has a significant effect on the photoluminescence of SnO2 films. The influence is very different in oxygen and nitrogen. A 'red shift' of the peaks of photoluminescence appeals when samples are annealed in O2 atmosphere at 300-500℃,while the emission peaks of annealing samples in N4 or H2 exhibit a 'blue shift'. The change of emission peaks of the SnO2 films may be attributed to the change of oxygen vacancies in SnO2 films during annealing. Undoped tin oxide films have n-type extrinsic conduction. The Sn2+ ions, associated with the oxygen vacancies, and the residual Cl~ ions are both capable of being electronic donors and probably both are responsible for this extrinsic conduction. The free carrier concentration of the conduction band changes with changing oxygen vacancies after annealing in oxygen or nitrogen. The change of the earlier concentration causes the change of optical gap energy according to Bursein effect.The peaks of photolumine-scence are then shifted with the change of optical gap energy after heat-treatment.
出处
《发光学报》
EI
CAS
CSCD
北大核心
1990年第3期229-233,共5页
Chinese Journal of Luminescence
