Cu/Sn原子比对溅射法制备的Cu2SnS3薄膜性能的影响

The effect of Cu/Sn ratio on sputtered Cu2SnS3 thin film

利用磁控溅射法在玻璃基片上沉积Sn/Cu叠层前驱体并将前驱体在H2S:N2气氛中硫化制备Cu2SnS3薄膜。制备出Cu/Sn原子比不同的薄膜样品,利用X射线衍射仪、拉曼光谱仪、扫描隧道显微镜、紫外-可见-近红外分光光度计、Hall测量系统等表征手段对薄膜进行性能表征。研究了Cu/Sn原子比对Cu2SnS3薄膜性能的影响。结果表明,制备的薄膜是(^-131)晶向择优生长的Cu2SnS3多晶薄膜,当Cu2SnS3薄膜的Cu/Sn原子比为1.91时,获得结晶性能优异、半导体性能满足太阳电池对吸收层要求的P型Cu2SnS3半导体薄膜,此薄膜在其光学吸收边具有较高的光吸收系数2.07×10^4 cm^-1、合适的载流子浓度6.6×10^18 cm^-3、较高的载流子迁移率5.1 cm^2 v^-1s^-1及较窄的禁带宽度0.97 eV。

Cu2SnS3 thin films were grown by sulfurization of sputtering stacked metal precursor in a H2S:N2 atmosphere.Different Cu/Sn composition ratios of films were prepared to study the effection of Cu/Sn atomic ratio on the properties of CTS thin films.The microstructures and Cu/Sn composition ratios of the films were characterized with X-ray diffraction and energy dispersive X-ray spectroscopy(EDS),respectively.The X-ray diffractograms show that the deposited films are exclusively oriented along the(-131)direction.The optical absorption coefficient and band gap of the films were estimated by means of transmission and reflection spectra measured at room temperature.Highly crystallized p-type CTS thin films were achieved when the Cu/Sn ratio is about 1.91.They have high absorption coefficient of 2.07×10^4 cm^-1,suitable carrier concentration 6.61018 cm^-3,high mobility 5.1 cm^2 v^-1s^-1 and narrow optical band gap 0.97 eV.it is a suitable candidate for thin film solar cell absorber materials.