“…A best fit to the experiments gives a resistance R 323K 0:233 G, which implies a resistivity 0:233 G cm. From these parameters, and by using [12] r 12, the dielectric relaxation time for the material is d 0:3 ms. Therefore, by extracting a mobility corresponding to holes 50 cm 2 =V s from the measurement of the cutoff frequency in the noise spectra in the shot noise region [14] (the sample is known to be p type [15]), and for an applied bias of 10 V, the transit time is T 0:08 ms, thus making accessible the shot noise condition ( T d ) for applied bias above a few tens of volts.…”