Excitation-density and excess-energy dependence of ultrafast dynamics of photoexcited carriers in intrinsic bulk CdTe

In this study, ultrafast dynamics of photoexcited carriers in an intrinsic CdTe film are investigated deeply and systematically as a function of carrier density and excess energy using femtosecond-resolved pump–probe transient differential transmission spectroscopy. A dynamic model is developed base...

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Autores principales:	Yicun Chen, Tianyu Shu, Tianshu Lai, Huizhen Wu
Formato:	article
Lenguaje:	EN
Publicado:	Elsevier 2021
Materias:	CdTe Ultrafast carrier dynamics Time-resolved spectroscopy Carrier-phonon scattering Radiative recombination Physics QC1-999
Acceso en línea:	https://doaj.org/article/2199c2267cf14dfda5cc20513e223c53
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spelling	oai:doaj.org-article:2199c2267cf14dfda5cc20513e223c532021-12-02T05:01:17ZExcitation-density and excess-energy dependence of ultrafast dynamics of photoexcited carriers in intrinsic bulk CdTe2211-379710.1016/j.rinp.2021.105047https://doaj.org/article/2199c2267cf14dfda5cc20513e223c532021-12-01T00:00:00Zhttp://www.sciencedirect.com/science/article/pii/S2211379721010366https://doaj.org/toc/2211-3797In this study, ultrafast dynamics of photoexcited carriers in an intrinsic CdTe film are investigated deeply and systematically as a function of carrier density and excess energy using femtosecond-resolved pump–probe transient differential transmission spectroscopy. A dynamic model is developed based on an interband transition absorption model in direct bandgap semiconductors by introducing the dynamics of thermalization, cooling and recombination of photoexcited carriers into the interband transition absorption model. Then, the model is used to best fit the measured ultrafast dynamics to retrieve the initial temperature of thermalized electrons and time constants of the thermalization, cooling and recombination dynamic processes as a function of carrier density and excess energy. The increase with carrier density and the decrease with excess energy of thermalization time constant reveal that thermalization process of photoexcited carriers is dominated by carrier-phonon scatterings. We find for the first time that cooling of thermalized carriers depend strongly on carrier density and excess energy, and cooling time constant varies in a wide range from 0.2 to 5 ps. It is also found that carrier recombination in the intrinsic CdTe film is dominated by the radiative recombination of electron-hole pairs, rather than Auger recombination as reported in doped CdTe films. These new results are very important to understanding of microscopic mechanism of relaxation processes of photoexcited carriers and applications of CdTe-based optoelectronic devices.Yicun ChenTianyu ShuTianshu LaiHuizhen WuElsevierarticleCdTeUltrafast carrier dynamicsTime-resolved spectroscopyCarrier-phonon scatteringRadiative recombinationPhysicsQC1-999ENResults in Physics, Vol 31, Iss , Pp 105047- (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	CdTe Ultrafast carrier dynamics Time-resolved spectroscopy Carrier-phonon scattering Radiative recombination Physics QC1-999
spellingShingle	CdTe Ultrafast carrier dynamics Time-resolved spectroscopy Carrier-phonon scattering Radiative recombination Physics QC1-999 Yicun Chen Tianyu Shu Tianshu Lai Huizhen Wu Excitation-density and excess-energy dependence of ultrafast dynamics of photoexcited carriers in intrinsic bulk CdTe
description	In this study, ultrafast dynamics of photoexcited carriers in an intrinsic CdTe film are investigated deeply and systematically as a function of carrier density and excess energy using femtosecond-resolved pump–probe transient differential transmission spectroscopy. A dynamic model is developed based on an interband transition absorption model in direct bandgap semiconductors by introducing the dynamics of thermalization, cooling and recombination of photoexcited carriers into the interband transition absorption model. Then, the model is used to best fit the measured ultrafast dynamics to retrieve the initial temperature of thermalized electrons and time constants of the thermalization, cooling and recombination dynamic processes as a function of carrier density and excess energy. The increase with carrier density and the decrease with excess energy of thermalization time constant reveal that thermalization process of photoexcited carriers is dominated by carrier-phonon scatterings. We find for the first time that cooling of thermalized carriers depend strongly on carrier density and excess energy, and cooling time constant varies in a wide range from 0.2 to 5 ps. It is also found that carrier recombination in the intrinsic CdTe film is dominated by the radiative recombination of electron-hole pairs, rather than Auger recombination as reported in doped CdTe films. These new results are very important to understanding of microscopic mechanism of relaxation processes of photoexcited carriers and applications of CdTe-based optoelectronic devices.
format	article
author	Yicun Chen Tianyu Shu Tianshu Lai Huizhen Wu
author_facet	Yicun Chen Tianyu Shu Tianshu Lai Huizhen Wu
author_sort	Yicun Chen
title	Excitation-density and excess-energy dependence of ultrafast dynamics of photoexcited carriers in intrinsic bulk CdTe
title_short	Excitation-density and excess-energy dependence of ultrafast dynamics of photoexcited carriers in intrinsic bulk CdTe
title_full	Excitation-density and excess-energy dependence of ultrafast dynamics of photoexcited carriers in intrinsic bulk CdTe
title_fullStr	Excitation-density and excess-energy dependence of ultrafast dynamics of photoexcited carriers in intrinsic bulk CdTe
title_full_unstemmed	Excitation-density and excess-energy dependence of ultrafast dynamics of photoexcited carriers in intrinsic bulk CdTe
title_sort	excitation-density and excess-energy dependence of ultrafast dynamics of photoexcited carriers in intrinsic bulk cdte
publisher	Elsevier
publishDate	2021
url	https://doaj.org/article/2199c2267cf14dfda5cc20513e223c53
work_keys_str_mv	AT yicunchen excitationdensityandexcessenergydependenceofultrafastdynamicsofphotoexcitedcarriersinintrinsicbulkcdte AT tianyushu excitationdensityandexcessenergydependenceofultrafastdynamicsofphotoexcitedcarriersinintrinsicbulkcdte AT tianshulai excitationdensityandexcessenergydependenceofultrafastdynamicsofphotoexcitedcarriersinintrinsicbulkcdte AT huizhenwu excitationdensityandexcessenergydependenceofultrafastdynamicsofphotoexcitedcarriersinintrinsicbulkcdte
_version_	1718400817681137664

Excitation-density and excess-energy dependence of ultrafast dynamics of photoexcited carriers in intrinsic bulk CdTe

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