Abstract: Understanding the carrier recombination processes in Sb₂Se₃ is crucial for enhancing its optoelectronic performance. Femtosecond transient absorption spectroscopy(fs-TAS), with its high-resolution advantages, provides rich optical information and serves as a powerful tool for investigating carrier recombination processes in Sb₂Se₃. This study obtained broadband transient absorption spectra of polycrystalline Sb₂Se₃ thin films under different excitation wavelengths and excitation densities. It was first confirmed that the excited-state absorption signals in the 650—1 100 nm range on longer time scales(time delay greater than 10 ps)originated from deep-bound carrier absorption, while the excited-state signals in the 900—1 050 nm range on shorter time scales(time delay less than 10 ps)were attributed to shallow-bound carrier absorption. Through the transient absorption dynamics of Sb₂Se₃, this study extracted the lifetimes of the free carriers and the cooling time of the hot carriers. Under 950 nm excitation, the average lifetime of free carriers ranged from 35.28 to 54.23 ps and decreased with increasing- DOI:10.3969/j.issn.1000-1565.2025.01.004基于瞬态吸收光谱的Sb₂Se₃载流子复合过程冯博浩,党伟,莫安明,董汶鑫,李志强,赵晓辉(河北大学 物理科学与技术学院,河北省光电信息材料重点实验室,河北 保定 071002)摘 要:了解Sb₂Se₃中的载流子复合过程对提高其光电性能至关重要.飞秒瞬态吸收光谱(fs-TAS)凭借高分辨率的优点能够获得丰富的光学信息,是研究Sb₂Se₃载流子复合过程的有力工具.本文测得不同激发波长和激发密度下的多晶Sb₂Se₃薄膜的宽带瞬态吸收光谱.首先证实在长时间尺度下(时间延迟大于10 ps)探测光为650~1 100 nm激发态吸收信号源于深束缚载流子吸收作用,并将短时间尺度下(时间延迟小于10 ps)探测光为900~1 050 nm激发态信号归因于浅束缚载流子吸收.通过Sb₂Se₃的瞬态吸收动力学曲线,提取出其自由载流子寿命和热载流子冷却时间:在激发波长为950 nm条件下,自由载流子平均寿命为35.28~54.23 ps,随着激发密度增加而减小;在激发波长为550 nm和750 nm条件下,热载流子冷却时间为0.17~0.48 ps,与激发密度成正比.关键词:Sb₂Se₃;载流子复合;瞬态吸收光谱;自由载流子寿命;热载流子冷却 中图分类号:O472 文献标志码:A 文章编号:1000-1565(2025)01-0034-09Carrier recombination processes in Sb₂Se₃ based on transient absorption spectroscopy FENG Bohao, DANG Wei, MO Anming, DONG Wenxin, LI Zhiqiang, ZHAO Xiaohui(Hebei Provincial Key Laboratory of Optoelectronic Information Materials, College of Physics Science and Technology, Hebei University, Baoding 071002, China)Abstract: Understanding the carrier recombination processes in Sb₂Se₃ is crucial for enhancing its optoelectronic performance. Femtosecond transient absorption spectroscopy(fs-TAS), with its high-resolution advantages, provides rich optical information and serves as a powerful tool for investigating carrier recombination processes in Sb₂Se₃. This study obtained broadband transient absorption spectra of polycrystalline Sb₂Se₃ thin films under different excitation wavelengths and excitation densities. It was first confirmed that the excited-state absorption signals in the 650—1 100 nm range on longer time scales(time delay greater than 10 ps)originated from deep-bound carrier absorption, while the excited-state signals in the 900—1 050 nm range on shorter time scales(time delay less than 10 ps)were attributed to shallow-bound carrier absorption. Through the transient absorption dynamics of Sb₂Se₃, this study extracted the lifetimes of the free carriers and the cooling time of the hot carriers. Under 950 nm excitation, the average lifetime of free carriers ranged from 35.28 to 54.23 ps and decreased with increasing- 收稿日期:2024-04-13;修回日期:2024-05-07 基金项目:国家自然科学基金资助项目(12275065);中央引导地方科技发展资金资助项目(236Z4305G);河北省光电信息材料重点实验室项目(22567634H) 第一作者: 冯博浩(1999—),男,河北大学在读硕士研究生,主要从事半导体载流子复合动力学方向研究.E-mail: 13373111085@163.com 通信作者: 赵晓辉(1978—),男,河北大学副教授,主要从事半导体载流子复合动力学方向研究.E-mail: xhzhao@hbu.edu.cn 第1期冯博浩等:基于瞬态吸收光谱的Sb₂Se₃载流子复合过程河北大学学报(自然科学版) 第45卷excitation density. Under 550 nm and 750 nm excitation, the time constant of hot carrier cooling times was in range of 0.17—0.48 ps and was proportional to the excitation density.

Key words: Sb₂Se₃, carrier recombination, transient absorption spectroscopy, free carrier lifetime, hot carrier cooling