Investigations on the physical origin of lateral photovoltage in PbS-colloidal quantum dot/Si heterojunctions

Abhale, Atul Prakash and Rao, Koteswara KSR and Pendyala, NB and Banerjee, A (2016) Investigations on the physical origin of lateral photovoltage in PbS-colloidal quantum dot/Si heterojunctions. In: JOURNAL OF PHYSICS D-APPLIED PHYSICS, 49 (11).

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Abstract

Restricted area heterojunctions, an array of lead sulfide colloidal quantum dots (PbS-CQDs) and crystalline silicon, are studied with a non-destructive remote contact light beam induced current (RC-LBIC) technique. As well as getting good quality active area images we observed an anomalous unipolar signal response for the PbS-CQD/n-Si devices and a conventionally expected bipolar signal profile for the PbS-CQD/p-Si devices. Interestingly, our simulation results consistently yielded a unipolar and bipolar nature in the signals related to the PbSCQD/n-Si and PbS-CQD/p-Si heterostructures, respectively. In order to explain the physical mechanism involved in the unipolar signal response of the PbS-CQD/n-Si devices, we propose a model based on the band alignment in the heterojunctions, in addition to the distribution of photo-induced excess majority carriers across the junction. Given that the RC-LBIC technique is well suited to this context, the presence of these two distinct mechanisms (the bipolar and unipolar nature of the signals) needs to be considered in order to have a better interpretation of the data in the characterization of an array of homo/heterojunctions.

Item Type:	Journal Article
Publication:	JOURNAL OF PHYSICS D-APPLIED PHYSICS
Publisher:	IOP PUBLISHING LTD
Additional Information:	Copy right for this article belongs to the IOP PUBLISHING LTD, TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND
Keywords:	lateral photovoltage; LBIC; PbS CQD; heterojunction
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	02 Apr 2016 09:12
Last Modified:	02 Apr 2016 09:12
URI:	http://eprints.iisc.ac.in/id/eprint/53535

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