Universal behaviour in the variable range hopping regime of copper ternarycompounds

Mott type variable range hopping conduction (VRH) below 50 K has been obser ved in several samples of CuInTe2. This set of data and those published ear lier on CuInSe2 and Si:B are used to check the validity over an extended ra nge of T/T-X towards high temperature of the scaling expression of the form rho = rho(0) exp [Af(T/T-X)] as proposed by Aharony et al. It is confirmed that all data including that of CdSe fall on a universal curve. From the k nowledge of the parameters A and T-X, one can get a better estimate of the critical temperature T-c in each sample, related to the crossover from Mott to Efros-Shklovskii type conduction.