A method to discern voltage dependent internal photoemission component from photoconductivity content in spectral response of metal-organic semiconductor-metal devices and evaluate the interface barriers

Kumar, Sandeep and Iyer, Kumar S Sundar (2019) A method to discern voltage dependent internal photoemission component from photoconductivity content in spectral response of metal-organic semiconductor-metal devices and evaluate the interface barriers. In: ORGANIC ELECTRONICS, 65 . pp. 215-221.

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Abstract

The ability to detect and determine a typically weak internal photoemission (IPE) signal from a usually strong photoconductivity (PC) signal within a spectral response (SR) measurement can be helpful in studying the interface properties of metal-semiconductor junctions, which are often critical for proper design and analysis of semiconductor electronic devices including organic photovoltaic devices. In this report, we propose a method to discern the voltage dependent IPE component from PC content in a measured SR of organic devices. The method is based on the ratio of SR measured at different voltage bias conditions in metal-organic semiconductor-metal devices. The separated IPE component, hence, can be used to estimate the associated interface barrier(s). The differentiation between IPE and PC is probably caused due to the barrier changing at the metal and organic semiconductor interface on the application of bias which causes a modulation in IPE signal with the applied bias. In this work, a theoretical basis for the method of characterisation has been developed. Based on the analysis, as an example, the barriers between 6,6] phenyl C61 butyric acid methyl ester (PCBM) and electrodes indium tin oxide and aluminium for different bias voltages have been evaluated. This simple and elegant method of studying metal and organic semiconductor barrier, when applicable, can be helpful in device design and characterisation.

Item Type:	Journal Article
Publication:	ORGANIC ELECTRONICS
Publisher:	ELSEVIER SCIENCE BV
Additional Information:	Copyright of this article belongs to ELSEVIER SCIENCE BV
Keywords:	Spectral response; Internal photoemission; Metal-semiconductor barrier; Bias dependent spectral response
Department/Centre:	Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Date Deposited:	25 Jan 2019 12:41
Last Modified:	25 Jan 2019 12:41
URI:	http://eprints.iisc.ac.in/id/eprint/61428

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