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离子注入对ZnTe：O中间带光伏材料的微观结构及光学特性的影响

ISSN号：1000-3290
期刊名称：《物理学报》
时间：0
分类：TN305.3[电子电信—物理电子学]
作者机构：[1]南京大学电子科学与工程学院,南京210093, [2]Department of Electronic Materials Engineering, Research School of Physics and Engineering, the Australian National University, Canberra 2601, Australia
相关基金：国家重点基础研究发展计划（批准号：2011CB302003）; 国家自然科学基金（批准号：61025020,60990312,61274058,61322403,61271077,11104130,11104134）; 江苏省自然科学基金（批准号：BK2011437,BK2011556,BK20130013）; 江苏省高等学校优势学科发展项目; 澳大利亚研究基金会创新项目（批准号：DP1096918）资助的课题

作者：甄康, 顾然[1], 叶建东[1,2], 顾书林[1], 任芳芳[1], 朱顺明[1], 黄时敏[1], 汤琨[1], 唐东明[1], 杨燚[1], 张荣[1], 郑有炓[1]

关键词：中间带, 离子注入, 高失配合金, II-VI族半导体, intermediate band, ion implantation, highly mismatched alloys, group II-VI semiconductors

中文摘要：

Ⅱ-Ⅵ和Ⅲ-Ⅴ族高失配合金半导体是新型高效中间带太阳电池的优选材料体系,但中间带的形成及其能带调控等关键问题仍未得到有效解决.采用氧离子注入方式,在非平衡条件下对碲化锌（Zn Te）单晶材料实现了等电子掺杂,深入研究了离子注入对Zn Te：O材料的微观结构和光学特性的影响.研究表明：注入合适浓度的氧离子（2.5×10^18cm^-3）将会形成晶格应变,并诱导1.80 e V（导带下0.45 e V）中间带的产生;而较高浓度（2.5×10^20cm^-3）的氧离子会导致Zn Te注入层表面非晶化,并增强与锌空位相关的深能级（～1.6 e V）发光.时间分辨光致发光结果显示,离子注入诱导形成的中间带主要是和氧等电子陷阱束缚的局域激子发光有关,载流子衰减寿命较长（129 ps）.因此,需要降低晶格紊乱度和合金无序,实现电子局域态向扩展态的转变,从而有效调控中间带能带结构.

英文摘要：

Group Ⅱ-Ⅵ and Ⅲ-Ⅴ highly mismatched alloys are promising material systems in the application of high efficiency intermediate-band solar cell（IBSC）, however, the key issues including band engineering of intermediate band still remain challenging. In this study, Zn Te：O alloys have been produced by isoelectric oxygen implantation into Zn Te single crystal,and the influences of implantation on the microstructural and optical properties of Zn Te：O have been investigated in detail. It is found that a proper dose of oxygen ions can lead to a compressive strain in the lattice and induce the formation of intermediate band located on the energy level of ～0.45 e V below the conduction band. While a high dose of oxygen ions causes Zn Te surface layer to become amorphous and enhances the deep level emission around 1.6 e V,which is related to Zn vacancies. Results of resonant Raman and time-resolved photoluminescence spectra indicate that implantation induced intermediate band is related to the localized exciton emission bound to oxygen isoelectric trap,and the associated photo excited carriers have a relatively long decay time. This suggests that the reduction of lattice distortion and alloy disorder may be needed for converting localized states of the intermediate band into extended states,which is crucial to realize high efficiency Zn Te：O based IBSCs.