射频磁控溅射法制备SnS_2薄膜结构和光学特性的研究

采用射频磁控溅射法溅射SnS_2靶,在玻璃基片上以不同射频功率和氩气压强制备一系列薄膜样品,研究了不同工艺条件对薄膜特性的影响。利用X射线衍射(XRD)和拉曼光谱(Raman)对薄膜样品的晶体结构和物相进行表征分析。利用X射线能量色散谱(EDS)、紫外-可见-近红外分光光度计(UV-Vis-NIR)对SnS_2薄膜的化学组分、光学特性等进行测试,计算或分析了SnS_2薄膜样品的组分原子比、光学常数和光学带隙。结果表明:制备SnS_2薄膜的最佳工艺条件为射频功率60 W、氩气压强0.5 Pa。在该条件下,所制备的SnS_2薄膜沿(001)晶面择优取向生长,可见光透过率和折射率较高,消光系数较小,直接带隙为2.81 e V。在此基础上,进一步制备了n-SnS_2/p-Si异质结器件。器件具有良好的整流特性及弱光伏特性,反向光电流随光照强度的增加而增大。器件的光电导机制是由SnS_2禁带中陷阱中心的指数分布所控制。

Structural and Optical Properties of SnS2 Films Prepared by RF Magnetron Sputtering

A series of SnS2 thin films were deposited on glass substrates by RF magnetron sputtering a SnS2 target. The effects of the preparation conditions on the properties of the films were studied. The crystal and phase structure of the thin films were investigated by X-ray diffraction and laser Ra-man spectroscopy. The chemical composition, optical properties of the SnS2 thin films were charac-terized by energy disperse X-ray spectroscopy, ultraviolet-visible-near infrared spectrophotometry ( UV-Vis-NIR) . The atomic ratio, optical constants and bandgap of SnS2 thin film were calculated and analyzed. The results show that the optimal condition for SnS2 thin films is the sputtering power of 60 W and argon pressure of 0. 5 Pa. The film is aligned along (001) preferred orientation, the transmittance and refractive index are high in the visible region, the extinction coefficient is small, and the direct bandgap is 2. 81 eV. The n-SnS2/p-Si heterojuction devices were fabricated. The de-vices exhibit good rectifying behaviors and weak photovoltaic properties. The photocurrent under the reverse bias voltage is increased with the increasing of illumination intensity. The photoconducting mechanism of the devices is controlled by the presence of exponential distribution of trap centers in the forbidden band of SnS2 .