Sentaurus modelling of 6.9% Cu₂ZnSnS₄ device based on comprehensive electrical & optical characterization

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• 作者：Aobo Pu¹ ; Fajun Ma¹ ; Chang Yan ; Jialiang Huang ; Kaiwen Sun ; Martin Green ; Xiaojing Hao ; ^{xj.hao@unsw.edu.au}
• 关键词：CZTS ; Characterization ; Modelling ; Interface recombination ; Bandgap fluctuation ; Lifetime
• 刊名：Solar Energy Materials and Solar Cells
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：160
• 期：Complete
• 页码：372-381
• 全文大小：1162 K
• 卷排序：160

文摘

Interface recombination was investigated through tuning interface recombination velocity in device model so that a fraction of simulated QEs, related to photons absorbed in near-interface regions, match that of measured QEs. This method yielded an interface velocity of 105 cm/s in turn suggesting the existence of defect-populated hetero-interface in CZTS device. Effective lifetime of device model was calculated with various interface recombination velocities and bulk lifetimes at Voc bias. By matching the mean lifetime determined from TRPL, we found a bulk lifetime of 28.8 ns. Gaussian-distributed bandgap model was used to numerically analyse the disorder-induced tailing states in CZTS absorber through fitting of QE tail and RTPL spectra. Bandgap-fluctuation amplitude of 120 meV was obtained. This, when projected into uniform 2D device, equivalents to a narrowed bandgap of 1.37 eV. Our model forecasted that, with interface problem alone settled, the device Voc could be boosted to above 900 mV. Furthermore, device Voc could even reach up to 1 V when mitigation of these two problems comes to fruition.