Akademik Veri Yönetim Sistemi
International World Energy Conference, Kayseri, Türkiye, 3 - 04 Aralık 2021, ss.176-182
Semiconductor materials (CdS, CdTe, CdSe, ZnS and ZnSe) belonging to the AIIBVI group are widely used
in photodevice production due to their characteristic properties. On the other hand, the high vapor pressure (S,
Se, Te) of this group of semiconductors causes defects to occur during production. For this reason, it is a
difficult technological process to produce the said materials perfectly on heated substrate surfaces. With the
effect of temperature, defects such as donor cadmium interstitials (Cdi) and acceptor sulphur, tellurium,
selenium cavities (VS, VTe, VSe) are formed in the crystal structure, giving the structure n-type electrical
conductivity. Film formation on a heated substrate surface occurs by islet growth mechanism and displays a
porous structure. This situation hinders the production of nano-sized photodevices. As can be seen, it is
important to develop new technological methods in the production of non-porous nanoscale semiconductor
films with high vapor pressure. Film production is carried out on the surface of the cooled substrates with the
cryogenic substrate effect mechanism designed by us. This apparatus consists of two main parts, the cooler
and the reactor parts. In the cooler part, there is a copper tube that can circulate liquid nitrogen for cooling the
samples, and in the reactor part, there is the saturated vapor of the evaporated material. The film formation
takes place thanks to the equal sized clusters carried from the saturated vapor medium to the substrate surface.
The formation of clusters in saturated vapor environment will prevent the occurrence of Cdi and VTe defects.
In this study, CdTe films were produced in the substrate temperature range of 100-300 K and their
characteristics were investigated. From the XRD diffraction patterns, it was observed that there was reflection
from the (111), (220) and (311) planes of the cubic structure. The energy band gap of the film produced at a
substrate temperature of 200 K was calculated as Eg = 1.53 eV. From electrical measurements, the resistivity
of the film produced at 200 K substrate temperature was calculated as ρ=6.63x103 Ohm.cm and carrier density
N=5.68 x1016 cm-3
. The films produced from the hot point probe method and Hall measurements was found to
have p-type electrical conductivity. From the initial results, it was understood that low-cost photodevices can
be widely produced on the basis of high vapor pressure semiconductors using the cryogenic substrate
technique.