Wüest M. 51 Wykes M. 82 Yamaguchi M. 17 Ybarra G. 129 Yubero F ...

JUNE 28 WEDNESDAY AFTERNOON
JS1-WeA-P.3 OPTICAL CHARACTERIZATION OF VACUUM EVAPORATED
CdZnTe THIN FILMS DEPOSITED BY STACKED LAYER METHOD. G.G. Rusu, M. Rusu,
M. Girtan. Faculty of Physics, “Al.I. Cuza” University, B-dul Carol I, No. 11, Iasi, Romania (e-mail:
rusugxg@uaic.ro)
The interest in the study of CdZnTe (CZT) alloys in thin films has been increased due to their important
applications in technology of thin film devices as solar cells, photo-detectors, gamma-ray detectors,
etc.
Among other preparation techniques of CZT, the physical vapour deposition is often preferred. In
such method, the evaporation of CdTe and ZnTe mixed powder or co-evaporation from dual CdTe
and ZnTe sources are frequently used. An inconvenient of these procedures is the difficulty to control
of Zn content in as evaporated CdZnTe films due to the vapour pressure difference between
CdTe and ZnTe and to the lower sticking coefficient of Zn.
To avoid this inconvenient, in present paper, a modified two source evaporation technique was used
to prepare CdZnTe thin films. Namely, during film deposition, the film substrates, placed onto a rotating
disk, passed successively with constant rate over the CdTe powder and metallic Zn evaporation
sources respectively, separated between them by two glass cylinders. In this way, nanolayered
CdTe/Zn structures with uniform Zn content were deposited. The structural and optical properties of
as deposited CdZnTe films were investigated.
Depending on the preparation conditions, both quasi-amorphous and oriented (111) polycrystalline
films were obtained. Also, depending on Zn content and heat treatment, the value of optical band
gap, E g , for studied films ranged between 1.48 eV and 1.63 eV.
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