Photoelectric properties of highly conductive samarium-doped cadmium telluride thin films for photovoltaic applications.

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Author: M.F. Al-Kuhaili
Date: Jan. 1, 2021
From: Solar Energy(Vol. 213)
Publisher: Elsevier Science Publishers
Document Type: Report; Brief article
Length: 271 words

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Abstract :

Keywords Cadmium telluride; Doping; Samarium; Electrical properties; Optical properties; Current--voltage; Schottky barrier Highlights * Samarium-doped cadmium telluride thin films were deposited by thermal evaporation. * The films were polycrystalline with smooth surfaces. * The band gap of CdTe decreased by 0.1 eV due to Sm doping. * The electrical resistivity of CdTe was reduced by eight orders of magnitude. * The conductivity of CdTe was changed from p- to n-type. * Ohmic contacts with CdTe were formed. Abstract Cadmium telluride (CdTe) is one of the most important materials for photovoltaic applications. CdTe-based solar cells have significantly high light-to-current conversion efficiency. However, further improvement of the efficiency is affected by two major problems: high electrical resistivity of CdTe and the difficulty to form ohmic contacts with this material. Extrinsic doping has been employed to rectify these problems; in particular, samarium is a rare-earth element that is characterized by its excellent electrical conductivity, high valence, and low oxidation affinity. In this work, thermally evaporated samarium-doped CdTe thin films were deposited with a samarium concentration of 0--6.2 at%. After doping, there were drastic changes in the photoelectric properties of the films, as demonstrated by: (i) conversion of CdTe from p- to n-type material, (ii) reduction of electrical resistivity by eight orders achieving the lowest value of 7.6 x 10.sup.-2 [OMEGA]·cm, (iii) formation of ohmic contacts to CdTe, and (iv) reduction of the optical bandgap, which enhanced the absorption of solar radiation. Author Affiliation: Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia Article History: Received 20 August 2020; Revised 8 November 2020; Accepted 11 November 2020 Byline: M.F. Al-Kuhaili [kuhaili@kfupm.edu.sa]

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Gale Document Number: GALE|A648932521