不同Sb含量p-SnO2薄膜的制备和特性

采用化学气相沉积方法, 利用Sb₂O₃/SnO作为源材料, 在蓝宝石衬底上制备出不同Sb掺杂量的SnO₂薄膜, 并在此基础上制作出p-SnO₂:Sb/n-SnO₂同质p-n 结器件. 研究表明, 随着Sb含量的增加, 样品表面变得平滑, 晶粒尺寸逐渐增大, 且晶体质量有所改善, 发现少量Sb的掺入可以起到表面活化剂的作用. Hall测量结果证实适量Sb的掺杂可以使SnO₂呈现p型导电特性, 当Sb₂O₃/SnO的质量比为1:5时, 其电学参数为最佳值. 此外, p-SnO₂:Sb/n-SnO₂同质p-n结器件展现出良好的整流特性, 其正向开启电压为3.4 V.

Fabrications of different Sb content p-SnO2 thin films

Tin oxide (SnO₂) is a wide-band-gap semiconductor with a bandwidth of 3.6 eV at room temperature, which is widely used in many fields, such as gas sensors, transparent electrodes and optoelectronic devices due to its high optical transparency, low resistivity, and higher chemical and physical stability. However for the real applications of SnO₂ based optoelectronic devices, it is necessary to obtain both n-type and p-type SnO₂ materials. Unfortunately, SnO₂ is intrinsically an n-type semiconductor material, therefore most efforts have been made to obtain p-type SnO₂ materials. In this paper, SnO₂ thin films with different Sb12 concentrations are grown on Al₂O₃ substrates by chemical vapor deposition method through using Sb₂O₃ and SnO as reaction source. The surface morphology, elemental concentration, and structural properties of SnO₂ thin films with different Sb concentrations are investigated by field-emission scanning electron microscopy, energy-dispersive spectroscopy and X-ray diffraction, respectively. As the Sb content increases, the SnO₂ thin films become more smooth and the grain size increases, indicating that the crystal quality of the thin film is improved. It is also found small amount of Sb doping of SnO₂ thin film can be act as a surfactant. Moreover, the Hall measurement results indicate that the Sb doped SnO₂ thin film has a p-type conductivity for an optimum Sb₂O₃/SnO mass ratio of 1:5. The optical absorption spectrum measurement indicates that the energy gap of sample is evidently blue-shifted with increasing Sb doping concentration. Furthermore, the Sb doped p-SnO₂/n-SnO₂ thin film homojunction is successfully fabricated to verify the p-type conductivity of Sb doped SnO₂. The Sb doped p-SnO₂/n-SnO₂ homojunction device shows good rectifier characteristics, and its forward-turn-on voltage is 3.4 V.