Cadmium zinc telluride crystals were grown using the traveling heater method (THM) under micro gravity conditions on board of Foton-M4 spacecraft, and a reference crystal was grown on Earth under gravity conditions. Structure, chemical and phase compositions of these crystals, their optical characteristics and microhardness were compared. It can be concluded that the THM growth in microgravity has a positive effect on CZT crystals, since they have more homogeneous composition and their structural perfection is improved as compared with the crystals grown under terrestrial conditions, which results in improvement of electric and optical characteristics. (C) 2016 Elsevier B.V. All rights reserved.