Electrical transport properties of p-GaTe grown by directional freezing method

p-type GaTe single crystals have been grown using the directional freezing method with different growth rates. Temperature-dependent Hall effect and resistivity measurements were carried out in the 80–325 K temperature range and at 1.6 T magnetic field. The free carrier concentration in the exhaust region was in the range of 9 × 10 15 –8 × 10 16 cm −3 for growth rates of 3.3–0.39 µm s −1 and the hole mobility at 300 K ranged from 4.8 to 21 cm 2 V −1 s −1 . A systematic dependence of the hole carrier concentration and room temperature hole mobility on the growth rate was not observed. From temperature-dependent Hall measurements, we have found that the compensation ratio N D / N A was in the range of 0.39–0.69 regardless of the growth rate. The highest mobility of 342 cm 2 V −1 s −1 at 100 K was achieved after annealing at 200 °C for 30 min. The fitting of the temperature-dependent free carrier concentration, using the single acceptor–single donor model, was used to determine the compensation ratio. Finding N max ( m *) 3/2 = 3.15 indicates high effective mass for holes or the possibility of a few close maxima of valence band edges with different effective masses.