The present invention relates to the field of semiconductor processing and provides apparatus and methods that improve chemical vapor deposition (CVD) of semiconductor materials by promoting more efficient thermalization of precursor gases prior to their reaction. In preferred embodiments, the invention comprises heat transfer structures and their arrangement within a CVD reactor so as to promote heat transfer to flowing process gases. In certain preferred embodiments applicable to CVD reactors transparent to radiation from heat lamps, the invention comprises radiation-absorbent surfaces placed to intercept radiation from the heat lamps and to transfer it to flowing process gases.