We report on the growth and characterization of mercury cadmium telluride (MCT) heterostructures grown by isothermal vapor phase epitaxy (ISOVPE) and vapor phase epitaxy (VPE). This report consists of the use of both ISOVPE and VPE methods for growing wider band gap MCT on narrow band gap MCT, the compositional and structural characterization of as‐grown layers, and the use of two zone Hg ampoules for carrier concentration control. The crystal perfection of some heterostructures is as good as that of the ISOVPE‐grown layers. The carrier concentrations and mobilities of the ISOVPE‐grown layers are substantially improved by a two zone Hg annealing technique.