Impact of trap filling on carrier diffusion in MAPbBr3 single crystals

Ganesh, N and Ghorai, A and Krishnamurthy, S and Banerjee, S and Narasimhan, KL and Ogale, SB and Narayan, KS (2020) Impact of trap filling on carrier diffusion in MAPbBr3 single crystals. In: Physical Review Materials, 4 (8).

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Abstract

We present experimental evidence showing that the effective carrier diffusion length Ld and lifetime � depend on the carrier density in MAPbBr3 single crystals. Independent measurements reveal that both Ld and � decrease with an increase in photocarrier density. Scanning photocurrent microscopy is used to extract the characteristic photocurrent Iph decay-length parameter Ld, which is a measure of effective carrier diffusion. The Ld magnitudes for electrons and holes are determined to be �13.3 and �13.8μm, respectively. A marginal increase in uniform light bias (�5�1015photons/cm2) increases the modulated photocurrent magnitude and reduces the Ld parameter by a factor of 2 and 3 for electrons and holes, respectively, indicating that the recombination is not monomolecular. The Ld variations are correlated to the features in photoluminescence lifetime studies. Analysis of lifetime variation shows intensity-dependent monomolecular and bimolecular recombination trends with recombination constants determined to be �9.3�106s-1 and �1.4�10-9cm3s-1, respectively. Based on the trends of Ld and lifetime, it is inferred that the sub-band-gap trap recombination influences carrier transport in the low-intensity excitation regime, while bimolecular recombination and transport dominate at high intensity. © 2020 American Physical Society.

Item Type:	Journal Article
Publication:	Physical Review Materials
Publisher:	American Physical Society
Additional Information:	copyright to this article belongs to American Physical Society
Keywords:	Diffusion; Energy gap; Photocurrents; Single crystals, Bimolecular recombination; Carrier diffusion length; Experimental evidence; Independent measurement; Modulated photocurrent; Photocarrier densities; Photoluminescence lifetime; Scanning photocurrent microscopies, Semiconductor quantum wells
Department/Centre:	Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Date Deposited:	18 Nov 2020 09:36
Last Modified:	18 Nov 2020 09:36
URI:	http://eprints.iisc.ac.in/id/eprint/66917

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