The effect of radiative heat transfer in metalorganic vapor-phase epitaxial growth of GaN on temperature distribution and chemical state was studied. We compared numerical simulations performed by using four kinds of models for the quartz absorptivity, transmissivity and reflectivity. The models are a transparent-body model, a blackbody model and two models using the experimental data measured at room temperature and at 1073 K by Fourier transform infrared spectroscopy. Numerical simulation using these models exhibited different results in temperature and chemical states, indicating that absorption of the quartz optical property at the elevated temperature is important to calculate accurate temperature field and chemical reactions. (c) 2004 Elsevier B.V. All rights reserved.