Charge transfer along localized states in InSe and InSe⟨Sn⟩ single crystals

It is established that at temperatures T < 200 K hopping conductivity with variable hopping length exists across natural layers of undoped and doped (0.2 and 0.4 at % Sn) InSe single crystals in a constant electric field. The density of states near the Fermi level (N(F)=5.36 center dot 10(18)-1.72 center dot 10(19) eV(-1)center dot cm(-3)), the energy spread of the states (Delta E=0.028-0.040 eV), the localization radius (a=58 A degrees), and the average hopping length (R(av)=99.5-130 A degrees) in the temperature interval 100-200 K are evaluated. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3388822]