Structural and Optical Properties of ZnO1-xSx Thin Films Grown by Pulse Laser Deposition on Glass Substrates
Structural and Optical Properties of ZnO1-xSx Thin Films Grown by Pulse Laser Deposition on Glass Substrates
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DOI：
10.4028/www.scientific.net/msf.787.18
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发表时间：
2014-04
期刊：
影响因子：
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通讯作者：
Lei Zhang;Liangheng Wang;Ming Li;Xunzhong Shang;Yunhong He
中科院分区：
文献类型：
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作者：
Lei Zhang;Liangheng Wang;Ming Li;Xunzhong Shang;Yunhong He
在室温下，氧化锌具有3.4 eV的宽带隙和60 meV的大激子束缚能，是蓝色和紫外光电子器件以及用于光伏应用的透明导电氧化物薄膜的理想选择。对于半导体来说，特别是在光电子器件方面，带隙工程在器件开发中是非常重要的。与其他含有等量阴离子的氧化锌合金如ZnO1-xSx(ZnOS)相比，氧化锌与氧化镁和氧化镉的合金化已经得到了广泛的研究。在本工作中，采用脉冲激光沉积的方法在玻璃衬底上生长了高质量的ZnOS薄膜，所用靶材为硫化锌陶瓷靶材，氧分压在0~6Pa.得到了具有纤锌矿结构的ZnOS合金，X射线衍射分析表明，在整个成分范围内没有观察到明显的相分离现象。光学透过率测试表明，薄膜在可见光范围内的平均透过率约为80%。随着氧分压的增加，薄膜的吸收边首先向低能侧移动，当氧分压大于2Pa时，吸收边发生蓝移。计算得到薄膜的禁带宽度从3.06 eV变化到3.72 eV，呈现出先前报道的具有弯曲行为的非线性变化。
With a wide band gap of 3.4 eV and a large exciton binding energy of 60 meV at room temperature, ZnO is attractive for blue and ultra-violet optoelectronic devices, and transparent conducting oxide films for photovoltaic applications. For a semiconductor to be useful, particularly in reference to optoelectronic devices, band gap engineering is of great importance in device development. Alloying of MgO and CdO with ZnO has been studied extensively in comparison to other ZnO alloys incorporating equivalent anions like ZnO1-xSx (ZnOS). In this work, high-quality ZnOS thin films were grown on glass substrates by pulsed laser deposition using a ZnS ceramic target with varying O2 partial pressures between 0 and 6 Pa. ZnOS alloys with a wurtzite structure were achieved and no evident phase separation was observed in the whole composition range as determined by X-ray diffraction. The optical transmission measurements show that the average transmittance in the visible range of the films is about 80%. The absorption edges of the films first shift towards low-energy side with increasing the oxygen partial pressure and then blueshift when the oxygen partial pressure is over 2 Pa. The bandgap energies of the ZnOS films were calculated to change from 3.06 to 3.72 eV, showing a nonlinear variation with a bowing behavior that was previously reported.