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Title: Molybdenum oxide and molybdenum oxide-nitride back contacts for CdTe solar cells

Molybdenum oxide (MoO{sub x}) and molybdenum oxynitride (MoON) thin film back contacts were formed by a unique ion-beam sputtering and ion-beam-assisted deposition process onto CdTe solar cells and compared to back contacts made using carbon–nickel (C/Ni) paint. Glancing-incidence x-ray diffraction and x-ray photoelectron spectroscopy measurements show that partially crystalline MoO{sub x} films are created with a mixture of Mo, MoO{sub 2}, and MoO{sub 3} components. Lower crystallinity content is observed in the MoON films, with an additional component of molybdenum nitride present. Three different film thicknesses of MoO{sub x} and MoON were investigated that were capped in situ in Ni. Small area devices were delineated and characterized using current–voltage (J-V), capacitance–frequency, capacitance–voltage, electroluminescence, and light beam-induced current techniques. In addition, J-V data measured as a function of temperature (JVT) were used to estimate back barrier heights for each thickness of MoO{sub x} and MoON and for the C/Ni paint. Characterization prior to stressing indicated the devices were similar in performance. Characterization after stress testing indicated little change to cells with 120 and 180-nm thick MoO{sub x} and MoON films. However, moderate-to-large cell degradation was observed for 60-nm thick MoO{sub x} and MoON films and for C/Ni painted back contacts.
Authors:
; ;  [1] ; ; ;  [2]
  1. Department of Physics, Colorado State University, Fort Collins, Colorado 80523 (United States)
  2. Department of Mechanical Engineering, Colorado State University, Fort Collins, Colorado 80523 (United States)
Publication Date:
OSTI Identifier:
22479704
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films; Journal Volume: 33; Journal Issue: 4; Other Information: (c) 2015 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 42 ENGINEERING; 14 SOLAR ENERGY; CADMIUM TELLURIDES; DEPOSITION; DIFFUSION BARRIERS; ELECTROLUMINESCENCE; ION BEAMS; MOLYBDENUM OXIDES; NICKEL; PERFORMANCE; SOLAR CELLS; SPUTTERING; STRESSES; TEMPERATURE DEPENDENCE; THIN FILMS; X-RAY DIFFRACTION; X-RAY PHOTOELECTRON SPECTROSCOPY