Presentation Details
| Defect Emission in CdCl2-treated CdSe Thin Films Abasi Abudulimu1, Xiaoming Wang1, Tyler Brau1, Jaroslav Kuliček2, Scott L.Wenner1, Adam B.Phillips1, Ebin Bastola1, Manoj K.Jamarkattel1, Vijay C.Karade1, Kiran Lamichhane1, Aparajita Dixit1, Bohuslav Rezek2, Yanfa Yan1, Michael J.Heben1, Randy J.Ellingson1. 1Wright Center for Photovoltaics Innovation and Commercialization (PVIC), Department of Physics and A, Toledo, OH, USA.2Faculty of Electrical Engineering, Czech Technical University in Prague, Prague, CT, Czech Republic |
Abstract
Here we systematically resolve radiative recombination pathways in CdCl₂-activated CdSe thin films using temperature- and injection-dependent photoluminescence (PL), time-resolved PL (TRPL), hyperspectral confocal PL mapping, and hybrid-DFT calculations. Chloride activation transforms nanocrystalline CdSe into dense micron-scale grains and sharpens the absorption edge, reducing the Urbach energy from ~85 meV to ~17 meV at room temperature. Three distinct emissive channels are identified: (i) a near-band-edge manifold that evolves from excitonic emission at low temperature to free-carrier recombination above ~120 K; (ii) a sub-gap band at Eg–0.45 eV that requires above-gap excitation and quenches with an activation energy of ~0.16 eV; and (iii) a deep infrared band near ~1.05 eV that is excitable by both above- and below-gap photons and retains microsecond lifetimes at 300 K. Spatial mapping reveals enhanced infrared emission at grain-boundary-rich regions where band-edge PL is suppressed and broadened. First-principles calculations support assignments to chlorine donors, selenium-vacancy-mediated recombination, and cadmium-vacancy–chlorine complexes.
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No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author.