High temperature mobility of CdTe

The Hall mobility of electrons μH is measured in CdTe in the temperature interval 450-1050°C and defined Cd overpressure in near-intrinsic conditions. The strong decrease of μH above 600°C is reported. The effect is explained within a model of multivalley conduction where both electrons in �1c minimum and in L1c minima participate. The theoretical description is based on the solution of the Boltzmann transport equation within the relaxation time approximation including the polar and acoustic phonon intravalley and intervalley scatterings. The �1c to L1c separation �E=0.29 - 10-4T (eV) for the effective mass in the L valley mL=0.35m0 is found to best fit the experimental data. Such �E is about four times smaller than it is predicted by first-principle calculations. © 2001 American Institute of Physics

High-temperature conductivity of solid and liquid CdTe

Conductivity of CdTe single crystals fabricated in our laboratory by vertical gradient freeze method was studied at temperatures 400-1200 degreesC. Two clear slopes are seen - 0.7 eV in the solid and 4.6 eV in the liquid. Experimental value of electrical conductivity at the melting point 10 Omega (-1)cm(-1) was observed. A model explaining the experimental data is suggested. (C) 2000 Elsevier Science B.V. All rights reserved

Galvanomagnetic properties of CdTe below and above the melting point

Temperature dependence of conductivity � and Hall coefficient RH is measured by DC and AC methods at temperatures between 600-1180°C. Two experimental approaches are used. Galvanomagnetic measurements at defined temperature and Cd or Te pressure are performed in solid samples in the whole field of stability of solid in the pressure-temperature (P-T) diagram. Galvanomagnetic measurements define temperature both in solid and in liquid phase. The typical semiconducting character of � and 1/|eRH|, when both parameters increase with temperature, is observed also in the liquid. The negative sign of RH is observed above 600°C within the whole region of stability of solid, both at Cd and at Te saturation, and RH < 0 both in solid and liquid. 1/|eRH| reaches 5 � 1019 cm-3 at 1180°C and the corresponding Hall mobility is 20 cm2/Vs. Three slopes characterize the temperature dependence of a 0.7 eV in the solid CdTe below the melting point 1092°C and 4.6 eV in the liquid phase at 1092°C < T < 1160°C. Above 1160°C, conductivity increases moderately with the slope 0.8 eV. The experimental data for solid CdTe are evaluated by a theoretical model, including electrons from both the central minimum (�-point) and four satellite minima (L-point) of the Brillouin zone. The ab initio results fit our experimental data after small modifications very well