1. V. K. Dubovoi, I. Ya. Kucherov, and V. I. Shtepovskii, Ukr. Fiz. Zh.,11, No. 4, 383 (1966);
2. N. D. Borisenko, F, F. Kodzhespirov, L. A. Mozharovskii, and A. G. Okhrimenko, Materials and Instruments of Radioelectronics [in Russian], Dnepropetrovsk (1968), p. 17.
3. I. S. Pavlov and G. S. Kucherenko, Izmeritel. Tekh., No. 4, 43 (1967).
4. V. M. Korsun' and A. M. Nemchenko, Radiophysics and Semiconductor Electronics [in Russian], Dnepropetrovsk (1967), p. 74.
5. Indradev and G. Garlick, Brit. J. Appl. Phys.,18, 1 (1967); A. Goltzberger and W. Shockley, J. Appl. Phys.,31, 18 (1960).