Sketch of the measurement set-up.
The schematics of the α-TCT set-up.
Averaged current pulses for holes (left column) and electrons (right column) at various temperatures for (top row) and (bottom row) are shown for S57. The pulses for 2 K and 50 K overlap almost completely for both electron and holes. Note as well the similarity of electron pulses at 150 K and 295 K. Pulses from S52 and S79 are very similar and hence omitted.
The transit times for holes (a) and electrons (b) at various temperatures and fields are shown for S57. Note the double logarithmic scale. Lines are drawn for constant voltages in order to guide the eye.
The drift velocity is plotted against the electric field for different temperatures for S57. The superimposed solid lines are fits after Eq. (3) . The dotted line shows the saturation velocity for holes, which is independent of the temperature, see Fig. 6 . The electron saturation velocity is not constant.
The saturation velocity from effective mobility fits is plotted against the temperature for holes (a) and electrons (b). Note the zero-suppression of the y-axis. The hole saturation velocity is constant over the measured temperature range, whereas the electron saturation velocity is not.
The low-field mobility is plotted against the temperature on double-logarithmic scale. The inset shows the mobility for a zoomed range from 200 K to 300 K. The results for all three samples are shown: S52 as , S57 as , and S79 as ×. Superimposed are the fits (solid and short dashed line) for the APS + NIM model (see text) in the entire temperature range, and the only APS-only model (long dashed line) for .
The drift velocity (in ) for holes and electrons at various temperatures for three SUTs at (E ). The sample average is given in the last two columns.
The low-field mobility in for holes and electrons at various temperatures.
The fit results under the assumption of the APS-only model for holes (200 K–300 K) and the APS + NIS model for holes (2 K–300 K) and electrons (2 K–150 K).
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