1. Instituto Politécnico Nacional, ESFM, Av. IPN, México City 07738, Mexico
2. Instituto Politécnico Nacional, UPIITA, Av. IPN, México City 07320, Mexico
3. Instituto Politécnico Nacional, ESIME, Av. IPN, México City 07738, Mexico
4. V. Lashkaryov Institute of Semiconductor Physics at NASU, Prospect Nauki 45, Kyiv 03028, Ukraine