Cu_(2)ZnSnS_(4)/Bi_(2)FeCrO_(6)半导体异质结的脉冲激光沉积法制备及其光电性能

Cu_(2)ZnSnS_(4)/Bi_(2)FeCrO_(6) semiconductor heterojunction grown by pulsed laser deposition and its optoelectronic properties

为充分发挥无机铁电氧化物双钙钛矿Bi_(2)FeCrO_(6)(BFCO)的光电特性,选择P型半导体化合物Cu_(2)ZnSnS_(4)(CZTS)作为空穴传输层与BFCO结合,构建半导体异质结。采用脉冲激光沉积法(PLD)制备得到上述两种多元化合物薄膜,SEM,AFM,EDS及XRD测试结果可证明所得产物形貌均匀致密、且符合化学计量比;原位逐层沉积技术可以抑制异质结界面缺陷和杂质的产生。着重研究了沉积温度及不同基底对薄膜性能的影响。采用基于可见光吸收谱的测试和Tauc方法分别估算BFCO和CZTS薄膜的禁带宽度,结果分别为2.23 eV和1.49 eV。研究结果表明:该异质结具有良好的整流特性;当电场强度在0.5 kV/cm到2.0 kV/cm之间时,结构漏电机制符合Schottky发射模型。

Inorganic Bi-based double perovskite oxide,Bi_(2)FeCrO_(6)(BFCO),has offered new opportunities for applications in burgeoning fields of optoelectronic and photovoltaic,due to its unique multiferroic properties at room temperature.The P-type direct-bandgap semiconductor Cu_(2)ZnSnS_(4)(CZTS)was adopted to couple with BFCO as hole transport layer,in order to construct BFCO/CZTS heterostructure.Pulsed laser deposition(PLD)technique was used to deposit above-mentioned polynary compound films on different substrates(i.e.FTO conductive glass,Nb-doped SrTiO 3 and Si/SiO 2/Ti/Pt).For the preparation of heterojunctions,the interfacial defects and impurities could be effectively restrained by in-situ layer-by-layer deposition technique.The systematical analysis according to SEM,AFM,EDS and XRD measurements verified that the morphology of the achieved stoichiometric films was basically uniform and dense.The impacts of deposition temperature on the product performance were emphatically investigated.The bandgap of obtained BFCO and CZTS films(i.e.2.23 eV and 1.49 eV,respectively)was estimated by using Tauc method based on visible absorption spectroscopy measurements.The results show that BFCO/CZTS heterojunction has a favorable rectifying characteristic;the leakage current mechanism is consistent with Schottky emission model when the electric field intensity spans from 0.5 kV/cm to 2.0 kV/cm.