Dalapati Goutam Kumar, Zhuk Siarhei, Masudy-Panah Saeid, Kushwaha Ajay, Seng Hwee Leng, Chellappan Vijila, Suresh Vignesh, Su Zhenghua, Batabyal Sudip Kumar, Tan Cheng Cheh, Guchhait Asim, Wong Lydia Helena, Wong Terence Kin Shun, Tripathy Sudhiranjan
Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 2 Fusionopolis Way, Innovis, #08-03, Singapore, 138634, Singapore.
NOVITAS, School of Electrical and Electronic Engineering, Block S2, Nanyang Technological University, Nanyang Avenue, Singapore, 639798, Singapore.
Sci Rep. 2017 May 2;7(1):1350. doi: 10.1038/s41598-017-01605-7.
We have investigated the impact of CuZnSnS-Molybdenum (Mo) interface quality on the performance of sputter-grown CuZnSnS (CZTS) solar cell. Thin film CZTS was deposited by sputter deposition technique using stoichiometry quaternary CZTS target. Formation of molybdenum sulphide (MoS) interfacial layer is observed in sputter grown CZTS films after sulphurization. Thickness of MoS layer is found ~142 nm when CZTS layer (550 nm thick) is sulphurized at 600 °C. Thickness of MoS layer significantly increased to ~240 nm in case of thicker CZTS layer (650 nm) under similar sulphurization condition. We also observe that high temperature (600 °C) annealing suppress the elemental impurities (Cu, Zn, Sn) at interfacial layer. The amount of out-diffused Mo significantly varies with the change in sulphurization temperature. The out-diffused Mo into CZTS layer and reconstructed interfacial layer remarkably decreases series resistance and increases shunt resistance of the solar cell. The overall efficiency of the solar cell is improved by nearly five times when 600 °C sulphurized CZTS layer is applied in place of 500 °C sulphurized layer. Molybdenum and sulphur diffusion reconstruct the interface layer during heat treatment and play the major role in charge carrier dynamics of a photovoltaic device.
我们研究了铜锌锡硫（CZTS）-钼（Mo）界面质量对溅射生长的铜锌锡硫（CZTS）太阳能电池性能的影响。采用化学计量比的四元CZTS靶，通过溅射沉积技术制备了CZTS薄膜。硫化后，在溅射生长的CZTS薄膜中观察到硫化钼（MoS）界面层的形成。当600℃硫化550nm厚的CZTS层时，MoS层的厚度约为142nm。在类似的硫化条件下，对于较厚的CZTS层（650nm），MoS层的厚度显著增加至约240nm。我们还观察到，高温（600℃）退火可抑制界面层中的元素杂质（铜、锌、锡）。向外扩散的Mo的量随硫化温度的变化而显著变化。扩散到CZTS层中的Mo和重构的界面层显著降低了太阳能电池的串联电阻并增加了并联电阻。当使用600℃硫化的CZTS层代替500℃硫化的层时，太阳能电池的整体效率提高了近五倍。钼和硫的扩散在热处理过程中重构了界面层，并在光伏器件的载流子动力学中起主要作用。
