Band alignments of different buffer layers (CdS, Zn(O,S), and In2S3) on Cu2ZnSnS4

被引：161

作者：

Yan, Chang ^{[1
]}

Liu, Fangyang ^{[1
]}

Song, Ning ^{[1
]}

Ng, Boon K. ^{[2
]}

Stride, John A. ^{[2
]}

Tadich, Anton ^{[3
]}

Hao, Xiaojing ^{[1
]}

机构：

[1] Univ New S Wales, Sch Photovolta & Renewable Energy Engn, Australian Ctr Adv Photovolta, Sydney, NSW 2052, Australia

[2] Univ New S Wales, Sch Chem, Sydney, NSW 2052, Australia

[3] Australian Synchrotron, Melbourne, Vic 3168, Australia

来源：

APPLIED PHYSICS LETTERS | 2014年 / 104卷 / 17期

基金：

澳大利亚研究理事会;

关键词：

SOLAR-CELLS; INTERFACE; PERFORMANCE; EFFICIENCY; OFFSET;

D O I：

10.1063/1.4873715

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

The heterojunctions of different n-type buffers, i.e., CdS, Zn(O,S), and In2S3 on p-type Cu2ZnSnS4 (CZTS) were investigated using X-ray Photoelectron Spectroscopy (XPS) and Near Edge X-ray Absorption Fine Structure (NEXAFS) Measurements. The band alignment of the heterojunctions formed between CZTS and the buffer materials was carefully measured. The XPS data were used to determine the Valence Band Offsets (VBO) of different buffer/CZTS heterojunctions. The Conduction Band Offset (CBO) was calculated indirectly by XPS data and directly measured by NEXAFS characterization. The CBO of the CdS/CZTS heterojunction was found to be cliff-like with CBOXPS = -0.24 +/- 0.10 eV and CBONEXAFS = -0.18 +/- 0.10 eV, whereas those of Zn(O,S) and In2S3 were found to be spike-like with CBOXPS = 0.92 +/- 0.10 eV and CBONEXAFS = 0.87 +/- 0.10 eV for Zn(O,S)/CZTS and CBOXPS = 0.41 +/- 0.10 eV for In2S3/CZTS, respectively. The CZTS photovoltaic device using the spike-like In2S3 buffer was found to yield a higher open circuit voltage (Voc) than that using the cliff-like CdS buffer. However, the CBO of In2S3/CZTS is slightly higher than the optimum level and thus acts to block the flow of light-generated electrons, significantly reducing the short circuit current (Jsc) and Fill Factor (FF) and thereby limiting the efficiency. Instead, the use of a hybrid buffer for optimization of band alignment is proposed. (C) 2014 AIP Publishing LLC.

引用

页数：4

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