1. A. V. Sachenko and Ju. V. Kryuchenko, Semicond. Phys. Quantum Electron. Optoelectron. 3, 150 (2000).
2. A. Shik, J. Appl. Phys. 74, 2951 (1993).
3. S. I. Gubarev, I. V. Kukushkin, S. V. Tovstonog, et al., Pis'ma Zh. Éksp. Teor. Fiz. 72, 469 (2000) [JETP Lett. 72, 324 (2000)].
4. D. V. Kulakovskii, S. I. Gubarev, and Yu. E. Lozovik, Pis'ma Zh. Éksp. Teor. Fiz. 74, 123 (2001) [JETP Lett. 74, 118 (2001)].
5. M. G. Lisachenko, E. A. Konstantinova, V. Yu. Timoshenko, and P. K. Kashkarov, Fiz. Tekh. Poluprovodn. (St. Petersburg) 36, 344 (2002) [Semiconductors 36, 325 (2002)].