Low-temperature galvanomagnetic studies of nominally undoped germanium subjected to intrinsic photoexcitation

The results of studying the heating of charge carriers by an electric field in nominally undoped Ge (with impurity concentrations of (N_a + N_g) ≤ 5 × 10¹³ cm^–3) subjected to interband illumination are reported. It is necessary in this situation to take into account two types of free charge carriers. In the case of such generation, the relation between the concentrations of electrons and holes depends to a large extent on the value of the electric field since this field differently affects the recombination coefficients of charge carriers and gives rise to new effects. The results of experimental studies of the conductivity σ and the Hall constant R_H in n-Ge and p-Ge at T = 4.2 K and at different intensities of intrinsic photoexcitation are reported. A model of interband recombination, which takes into account deep-level impurity centers, is suggested for explanation of the results