We have fabricated the Ti/[Formula: see text]-type GaAs Schottky diodes (SDs) by the DC magnetron deposition and thermal evaporation, cut from the same GaAs substrates, and we have made a comparative study of the current–voltage ([Formula: see text]–[Formula: see text]) measurements of both SDs in the measurement temperature range of 160–300[Formula: see text]K with steps of 10[Formula: see text]K. The barrier height (BH) values of about 0.82 and 0.76[Formula: see text]eV at 300[Formula: see text]K have been obtained for the sputtered and evaporated SDs, respectively. It has been seen that the apparent BH value for the diodes has decreased with decreasing temperature obeying the single-Gaussian distribution (GD) for the evaporated diode and the double-GD for the sputtered diode over the whole measurement temperature range. The increment in BH and observed discrepancies in the sputtered diode have been attributed to the reduction in the native oxide layer present on the substrate surface by the high energy of the sputtered atoms and to sputtering-induced defects present in the near-surface region. We conclude that the thermal evaporation technique yields better quality Schottky contacts for use in electronic devices compared to the DC magnetron deposition technique.

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In the present work, the thermal conductivity and electrical resistivity of the Al-0.25 Zr (wt.%) alloy have been investigated from 300 K to 600 K. The variations of thermal conductivity (K total) with temperature were measured by using a radial heat flow furnace. The electrical resistivity (ρ) measurements of the alloy depending on the temperature were performed using the standard four-point probe method. The electrical conductivity (σ) was obtained by using the measured electrical resistivity. The thermal conductivity and the electrical resistivity coefficients were determined from the graphs of thermal and electrical resistivity versus temperature for the alloy. The electronic thermal conductivity (K e) values were obtained from the Wiedemann-Franz and Smith-Palmer equations, and the values of K L were obtained by subtracting K e fromthe measured values (K total). K total is dominated by Ke, and K e varies between 208-198 W/mK. The K L decreases from 7.99 to 1.77 W/m K, and σ varies between 1.41x10 7-2.80x10 7 Ω-1 m-1 in the range of temperature 373-600 K. The enthalpy of fusion (ΔH) and the specific heat capacity (C p) during the transformation were determined. Thermal diffusivity (α) changes were calculated as a function of temperature from these obtained thermal data.

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