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Showing papers on "Mass action law published in 1972"


Journal ArticleDOI
TL;DR: In this paper, the infrared absorption between 400 and 4,000 cm-1 is measured as a function of carrier concentration for n-type GaAs at three different temperatures of 90°, 300° and 450K.
Abstract: The infrared absorption between 400 and 4,000 cm-1 is measured as a function of carrier concentration for n-type GaAs at three different temperatures of 90°, 300° and 450K. The absorption in the 800 to 2,000 cm-1 region is only due to the optical transition of free carriers. The free carrier absorptions arising from three scattering sources, i.e. acoustic and optical phonons, and ionized impurities, are numerically evaluated in the infrared region. At a constant wave number, 1,000 cm-1, a comparison of the theoretical cross section with the experimental value is performed and the degree of compensation of impurities (Nimp/Ne) for each sample is graphically determined using the total photon capture cross section vs. carrier concentration chart. The numerical results of the wave number and temperature dependences of free carrier absorption are in good agreement with the experimental data in the wide range of carrier concentrations from 1×1016 to 1×1018 cm-3. A relatively sharp peak is detected at =3,200 cm-1 at 90K. The absorption is suggested to occur by a transition from a deep impurity level (0.4 eV) to the conduction band.

29 citations


Journal ArticleDOI
TL;DR: In this article, the thermodynamic law of mass action is applied to the calculation of equilibrium conduction electron and hole concentrations in semiconductors, in addition to the intrinsic electron-hole excitation.
Abstract: The application of the thermodynamical law of mass action to the calculation of equilibrium conduction electron and hole concentrations in semiconductors is explained. The method can be applied to arbitrarily complicated systems of donors, traps, acceptors, etc., in addition to the intrinsic electron-hole excitation. The discussion is limited to small defect concentrations and quasifree charge carriers, so that the ideal-gas free energy and the Sackur-Tetrode entropy constant can be used. Exact solutions are straightforward but often so complicated that simplifying assumptions are useful. As an example the effect of compensation of donors is calculated as a function of temperature. The Fermi energy is simply related to the electron concentration.

5 citations