Measurement of positron mobility in Si at 30–300 K

The temperature dependence of positron motion in silicon (Si:[P]=4×{}10¹⁴ cm^-3) is studied experimentally by measuring the drift length of positrons in the space-charge region of an Au-Si surface-barrier diode. At 300 K the positron mobility is 110±{}15 cm² V^-1 s^-1, and it increases to 2800±{}1000 cm² V^-1 s^-1 at 30 K. Below 300 K the mobility varies with temperature in accordance with T^-3/2. This temperature dependence of carrier mobility is typical of scattering from longitudinal-acoustic phonons.