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Metal–Dielectric Transition in n‐ZnSe Obtained by Doping with Shallow Donor Impurity
Author(s) -
Kasiyan V. A.,
Nedeoglo D. D.,
Simashkevich A. V.,
Timchenko I. N.
Publication year - 1990
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221570135
Subject(s) - thermal conduction , impurity , condensed matter physics , activation energy , dielectric , materials science , doping , conductivity , electrical resistivity and conductivity , atmospheric temperature range , chemistry , thermodynamics , physics , optoelectronics , organic chemistry , quantum mechanics , composite material
By means of dosed variation from 2 × 10 16 to 2 × 10 18 cm −3 of the shallow donor Al impurity concentration in n‐ZnSe a transition from activated conductivity to non‐activated one is obtained in the low‐temperature limit. In the temperature range from 1.6 to 300 K the peculiarities of resistivity, Hall coefficient, and electron mobility dependences on temperature are investigated while transiting from a metallic conduction to an activated one. On the dielectric side of the transition as the temperature decreases the conduction with an activation energy ϵ 1 induced by electron excitation from the impurity states into the conduction band is replaced by the hopping conduction with a constant activation energy ϵ 3 , which in the lowest temperature region is transferred to a hopping conduction of variable activation energy. It is established that the replacement of the activated conduction by a metallic one occurs at N D = 1.3 × 10 17 cm −3 and takes place within the impurity band before it attains the bottom of the conduction band. The electron concentration at the transition from the metallic state to the dielectric one is continuously varied as a consequence of a chaotic distribution of donors in the crystal.