A MODIFIED TWO-STAGE PROCESS FOR THE PREPARATION OF
Zn(Te
x
Se
1x
) FILMS
R. Jeyakumar
1
*, G.K. Chadda
2
, S.T. Lakshmikumar
1
, and A.C. Rastogi
1
1
Materials Division, National Physical Laboratory, Dr. K.S. Krishnan Road,
New Delhi 110 012, India
2
Department of Physics and Astrophysics, University of Delhi, Delhi 110 007, India
(Communicated by J.B. Goodenough)
(Received April 27, 1998; Accepted April 27, 1998)
ABSTRACT
A modified low-pressure vapor-phase selenization process that enables con-
trolled incorporation of multiple chalcogens in ZnSe semiconductor thin films
has been demonstrated. Growth of polycrystalline ZnTe
x
Se
1-x
films and
modification of the Te/Se ratio by varying the reactor pressure have been
observed. Te incorporation results in the lowering of the band gap to 2.45 eV
from 2.65 eV for pure ZnSe and reduction in resistivity by a factor of 3. The
increased Te incorporation in the film correlates with the value estimated from
modeling of the gas dynamics of the system and is independently confirmed
by XRD. These results indicate that the Te
2
–Zn reaction is competitive with
the Se
5–7
–Zn reaction under the experimental conditions investigated. © 1999
Elsevier Science Ltd
KEYWORDS: A. semiconductors, A. thin films, B. vapor deposition, D.
electrical properties
INTRODUCTION
CuInSe
2
, CdTe, CdS, and ZnSe are among the II–VI and I–III–VI compound semiconductors
with a potential for large-scale photovoltaic applications. Incorporation of a second chalco-
gen is a new technique of optimizing the electronic and optical properties of both the absorber
materials such as CuIn(SSe)
2
and wide-band-gap materials such as Cd(SSe) and Zn(TeSe).
*To whom correspondence should be addressed.
Materials Research Bulletin, Vol. 34, No. 1, pp. 109 –114, 1999
Copyright © 1999 Elsevier Science Ltd
Printed in the USA. All rights reserved
0025-5408/99/$–see front matter
PII S0025-5408(98)00212-8
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