Calculations of Energy Shift of the Conduction Band-Edge in Doped and Compensated GaP

概要

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The energy shifts of the parabolic conduction band-edge at 77 and 300K with doping the Te-donor in GaP were calculated in the nondegenerate system for the two cases ; unintentional and intentional compensations, using the two models proposed by Hwang abd by Mahan. The total parabolic shift △EM（△EH）, and the contributions of the exchangeinteraction △μex（△Ee） and of the Coulomb interaction △μed（△Ec） calculated by the Mahan's model (Hwang's model), increase with increasing donor concentration in the unintentional compensation system at 300K. △μex is smaller than △μed whereas △Ee is much larger than △Ec, and △μex　<　△Ee and △μed > △Ec. △EM agrees well the experimental parabolic shift △δ while △EH　＞　△δ. The energy gap narrowing △EG calculated by the Mahan's model is much larger than the experimental energy gap narrowing △EC. The results are interppretd as follows. △μex fairly estimate the exchange interaction since the Mahan's model takes account of the anisotropy and multivalley effects. △μed reasonably estimates the Coulomb interaction since the Mahan's model takes account of the self-consistent interaction energy of the elentron-screened donor system. The overestimation of the hole-electron correlathon energy may be a reason for △EG　>　△EO.
Faculty of Engineering, Mie Universityの論文
1989-12-20