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Theoretical consideration on Urbach energy for doped III-V semiconductors
Dibya Prakash Kar1, P R Sagdeo1
1Materials Research Laboratory, Department of Physics, Indian Institute of Technology Indore, Khandwa Road, Indore 453552 Madhya Pradesh, India.
None:
This work develops an analytical model for quantitatively estimating the Urbach energyas a function of doping concentration in semiconductors with non-isovalent doping, accounting contributions from structural disorder, carrier-impurity interactions, and carrier-phonon interactions. In the first part of the paper, the contribution from carrier-impurity interaction is formulated as per the Halperin-Lax and Edwards model, the correction term due to structural disorder is included, and the carrier-phonon interaction contribution is formulated by analytically solving the correlation function for longitudinal-optical phonon-carrier interactions. The totalis expressed separately forn-type andp-type impurities, and the calculated values agree very well with the experimental data available in the literature for Group III-V semiconductors at 300 K. We further quantify the relative scaling of individual contributions with doping concentration at 300 K.
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