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Title: Deposition and characterization of Cd{sub 1−x}Mg{sub x}Te thin films grown by a novel cosublimation method

Photovoltaic cells utilizing the CdS/CdTe structure have improved substantially in the past few years. Despite the recent advances, the efficiency of CdS/CdTe cells is still significantly below their Shockley–Queisser limit. CdTe based ternary alloy thin films, such as Cd{sub 1−x}Mg{sub x}Te (CMT), could be used to improve efficiency of CdS/CdTe photovoltaic cells. Higher band gap Cd{sub 1−x}Mg{sub x}Te films can be the absorber in top cells of a tandem structure or an electron reflector layer in CdS/CdTe cells. A novel cosublimation method to deposit CMT thin films has been developed. This method can deposit CMT films of band gaps ranging from 1.5 to 2.3 eV. The cosublimation method is fast, repeatable, and scalable for large areas, making it suitable for implementing into large-scale manufacturing. Characterization of as-deposited CMT films, with x varying from 0 to 0.35, reveals a linear relationship between Mg content measured by energy dispersive x-ray spectroscopy and the optical band gap. Glancing angle x-ray diffraction (GAXRD) measurements of Cd{sub 1−x}Mg{sub x}Te films show a zinc-blende structure similar to CdTe. Furthermore, increasing Mg content decreases the lattice parameter and the grain size. GAXRD shows the films are under mild tension after deposition.
Authors:
; ;  [1] ; ;  [2]
  1. Department of Mechanical Engineering, Colorado State University, 1374 Campus Delivery, Fort Collins, Colorado 80523 (United States)
  2. Department of Physics, Colorado State University, 1875 Campus Delivery, Fort Collins, Colorado 80523 (United States)
Publication Date:
OSTI Identifier:
22258646
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films; Journal Volume: 32; Journal Issue: 2; Other Information: (c) 2014 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CADMIUM SULFIDES; CADMIUM TELLURIDES; DEPOSITION; EFFICIENCY; ELECTRONS; GRAIN SIZE; LATTICE PARAMETERS; LAYERS; PHOTOVOLTAIC CELLS; TERNARY ALLOY SYSTEMS; THIN FILMS; X-RAY DIFFRACTION; X-RAY SPECTROSCOPY; ZINC SULFIDES