Layer-dependent optical and dielectric properties of CdSe semiconductor colloidal quantum wells characterized by spectroscopic ellipsometry  

作　　者：Chenlin Wang Haixiao Zhao Xian Zhao Baoqing Sun Jie Lian Yuan Gao 

机构地区：[1]School of Information Science and Engineering,Shandong University,Qingdao 266237,China [2]Key Laboratory of Laser&Infrared System(Shandong University),Ministry of Education,Shandong University,Qingdao 266237,China [3]Center for Optics Research and Engineering(CORE),Shandong University,Qingdao 266237,China

出　　处：《Journal of Semiconductors》2025年第4期46-53,共8页半导体学报(英文版)

基　　金：supported by the National Natural Science Foundation of China(62205180);the Natural Science Foundation of Shandong Province(ZR2022QF029);the Taishan Scholar Program of Shandong Province(Young Scientist).

摘　　要：Semiconductor colloidal quantum wells(CQWs)with atomic-precision layer thickness are rapidly gaining attention for next-generation optoelectronic applications due to their tunable optical and electronic properties.In this study,we investigate the dielectric and optical characteristics of CdSe CQWs with monolayer numbers ranging from 2 to 7,synthesized via thermal injection and atomic layer(c-ALD)deposition techniques.Through a combination of spectroscopic ellipsometry(SE)and first-principles calculations,we demonstrate the significant tunability of the bandgap,refractive index,and extinction coefficient,driven by quantum confinement effects.Our results show a decrease in bandgap from 3.1 to 2.0 eV as the layer thickness increases.Furthermore,by employing a detailed analysis of the absorption spectra,accounting for exciton localization and asymmetric broadening,we precisely capture the relationship between monolayer number and exciton binding energy.These findings offer crucial insights for optimizing CdSe CQWs in optoelectronic device design by leveraging their layer-dependent properties.

关 键 词：CdSe CQWs bandgap spectroscopic ellipsometry monolayer number exciton binding energy 

分 类 号：O469[理学—凝聚态物理]