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Effects of CdCl 2 treatment on properties of CdTe thin films grown by evaporation at low substrate temperatures
Author(s) -
Bacaksiz E.,
Altunbaş M.,
Yılmaz S.,
Tomakin M.,
Parlak M.
Publication year - 2007
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.200710957
Subject(s) - annealing (glass) , microstructure , thin film , materials science , grain boundary , vacuum evaporation , analytical chemistry (journal) , grain size , absorption edge , chemistry , crystallography , band gap , composite material , nanotechnology , chromatography , optoelectronics
The structural, morphological and optical properties of vacuum‐evaporated CdTe thin films were investigated as a function of substrate temperature and post‐deposition annealing without and with CdCl 2 /treatment at 400°C for 30 min. Diffraction patterns are almost the same exhibiting higher preferential orientation corresponding to (111) plane of the cubic phase. The intensity of the (111) peak increased with the CdCl 2 /annealing treatment. The microstructure observed for all films following the CdCl 2 /annealing treatment are granular, regardless of the as‐deposited microstructure. The grain sizes are increased after the CdCl 2 /annealing treatment but now contain voids around the grain boundaries. The optical band gaps, E g , were found to be 1.50, 1.50 and 1.48 eV for films deposited at 200 K and annealed without and with CdCl 2 /treatment at 400°C for 30 min respectively. A progressive sharpening of the absorption edge upon heat treatment particularly for the CdCl 2 /treated was observed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)