, ,
Volume 14, Issue 1 (4-2006)
Abstract
The (Bi0.25 Sb0.75)2Te3 compound is a p-type thermoelectric semiconductor for application in
thermoelectric cooling systems. To fabricate this single crystal, required elements, Bi, Sb and Te with 5N
purity melted in quartz capsule at 10-6 torr pressure and rapidly quenched to room temperature. The sample
crystallized by zone melting method with the rate of 8 mm per an hour at 700 oC and for heat stress relieving
annealed at 370 oC.In this presentation; crystal growth process and effect of dopants on improving the
thermoelectric property of crystals will be reported. Structural studies by XRD show the expected phases
formed in single phase. Scanning electron microscopy (SEM) was used to characterize the quality of the
crystal growth. Maximum figure of merit Z = 3.15×10-3 K-1in optimum condition was obtained.
Dr. Hassan Zare Asl, Dr. Seyed Mohammad Rozati,
Volume 33, Issue 1 (3-2025)
Abstract
Fluorine (F)-doped tin oxide (FTO) thin films were spray-deposited onto soda lime glass substrate. The F doping concentration ([F]/[F]+[Sn] atomic ratio) varied from 0, 20, 30, and 40 at.% in the precursor solution. Due to the presence of the F in the SnO2 structure, the thin films texture was changed which was found to be in favor of mobility improvement. The mobility enhancement along with the carrier concentration raise, which result from substitution of O2- with F- that led to significant conductivity promotion in the doped thin films. Moreover, F doping caused transparency improvement and shift in the absorption edge towards lower wavelength in the prepared FTO thin films. Consequently, the FTO film derived from 30 at.% doping reached a resistivity, sheet resistance, and average transmittance of 2.08×10-1 Ω.cm, 16 Ω/sq, and 87.47%, respectively. The mentioned values provided a 1.65×10-2 Ω-1 of figure of merit for the FTO thin film.
