We have calculated the total emittance &egr;tofn‐type GaAs as a function of doping level and thickness in the temperature range between 300 and 1500 °K. &egr;tis related to the spectral emittance &egr;&lgr;, which in turn depends on the index of refraction, thickness, and absorption coefficient &agr;. To obtain a theoretical representation of &agr;, a model is constructed which includes contributions by the fundamental edge, interconduction band, and free carriers (acoustic and optical phonons and ionized impurities). Since this two‐parameter model offers a good description of assorted &agr; measurements with respect to wavelength, impurity level, and temperature, the evaluation of &egr;&lgr;is relatively straightforward. At each temperature, &egr;tis computed by the numerical integration of &egr;&lgr;over a wide wavelength range followed by normalization to &sgr;T4. The calculations show that &egr;tincreases with temperature and doping level. At 1300 °K, for a 1‐cm‐thick sample, as the carrier concentration rises from 1016to 1017cm−3, &egr;tincreases from 0.28 to 0.68, respectively. These results are compared with those for Ge and general comments are made on the &egr;tofp‐type and semi‐insulating GaAs. Finally, employing &egr;tas one of the parameters in the quasi‐steady state heat transfer/thermal stress model for dislocation generation in the Czochralski growth of GaAs, we explain the inherent difficulty encountered in pulling sizable defect‐free crystals in terms of the severe thermal strss generation in excess of the critical resolved shear stress. One realistic set of conditions that would lead to a dislocation‐free GaAs is small diameter (∼1 cm), light doping concentration (∼1016cm−3), and shallow ambient temperature gradient (<100 °K).