溶液法制备透明SnO2薄膜微观结构和光电性能研究

Microstructures and Photoelectric Properties of Transparent SnO2 Film Prepared by Solution Method

摘要:

氧化锡由于其优异的透明性和半导体性能及成本低廉、绿色环保等特点，逐渐成为透明氧化物半导体材料研究的热点。使用异丙醇((CH₃)₂CHOH)和乙醇(CH₃CH₂OH)为溶剂、二水合氯化亚锡(SnCl₂·2H₂O)为前驱体，通过旋涂法制备低成本且环保的透明SnO₂薄膜。采用同步热分析仪(TG-DSC)、激光共聚焦显微镜和霍尔效应测试仪等设备，对SnO₂薄膜的化学组分、微观结构和光电性能进行表征，探究溶剂和退火温度对透明SnO₂薄膜的影响及相关机制。研究结果表明：Sn²⁺在乙醇中的溶解性好，相应前驱体溶液的成膜质量高，薄膜致密平整；提高退火温度，薄膜内部杂质逐渐去除(215.6 ℃@CH₃CH₂OH)，经过400 ℃退火后SnO₂由非晶态向结晶态转变，且SnO₂的结晶度随着温度升高而逐渐增加；基于不同温度制备的SnO₂薄膜在可见光波段(390—780 nm)具备优异的透明性，在波长为390 nm时不同温度下的透射率分别为96.55%（250 ℃）、96.21% （300 ℃）、95.14%（350 ℃）、96.44%（400 ℃）和93.31%（500 ℃）；随着退火温度升高，SnO₂薄膜的霍尔迁移率先增大后减小，薄膜载流子浓度先降低后增大，优化后的SnO₂薄膜（@350 ℃）的霍尔迁移率最高可达19.54 cm²?V^-1·s^-1，而可控载流子浓度低至7.47×10¹² cm^-2。通过优化溶剂成分和退火温度，最终制备了表面平整、高度透明且具备优良半导体性能的SnO₂薄膜，其在透明电子应用方面具有巨大的潜力。

Abstract:

SnO₂ has gradually become a hot research topic of transparent oxide semiconductor materials due to its excellent transparency and semiconductor performance and low cost， green and other characteristics. In this paper， low cost and environmentally friendly transparent SnO₂ films were prepared by spin-coating method using isopropyl alcohol and ethyl alcohol as solvents and SnCl₂·2H₂O as precursor. The chemical compositions， microstructures， optical and electrical properties of SnO₂ thin films were characterized by synchronous thermal analyzer （TG-DSC）， laser confocal microscope and Hall effect tester and so on. The effects of solvent and annealing temperature on the transparent SnO₂ thin films and related mechanisms were explored. The results showed that the solubility of Sn²⁺ in ethyl alcohol was good， which was beneficial to improve the quality of the film， and the film prepared with the corresponding precursor solution is compact and smooth. With increasing the annealing temperature， the impurity in the film was gradually removed （215.6 ℃@CH₃CH₂OH）. The SnO₂ film crystallized after annealing at 400 ℃， and the crystallinity of SnO₂ increased with increasing the annealing temperature. The SnO₂ films prepared at different temperatures had excellent transparency in the visible band （390—780 nm）， and their transmittances at 390 nm were as follows： 96.55% （250 ℃）， 96.21% （300 ℃）， 95.14% （350 ℃）， 96.44% （400 ℃）， 93.31% （500 ℃）. With the increase of annealing temperature， the Hall mobility of SnO₂ films increased first and then decreased， and the sheet carrier concentration decreased first and then increased. The Hall mobility of the optimized SnO₂ film （annealed at @350℃） was up to 19.54 cm²?V^-1·s^-1， while the sheet carrier concentration was as low as 7.47×10¹² cm^-2. By optimizing solvent composition and annealing temperature， SnO₂ films with smooth surface， high transparency and excellent semiconductor properties have been prepared in this study， which have a great potential in transparent electronic applications.