CRYSTAL-GROWTH AND DIFFERENTIAL THERMAL-ANALYSIS OF AGGASE2

High quality AgGaSe2 single crystals with 20 mm in diameter and 55 mm in length have been grown by Bridgman technique. It is found that ther e is a second phase of Ag-rich Ga2Se3 (or named AgGa7Se11) in the AgGa Se2 crystal. It is concluded by discussions with the DTA results and t he phase diagram that single crystals grown from polycrystalline mater ials with stoichiometric composition must contain a second phase of Ag -rich Ga2Se3. This result is helpful for the heat treatment, in which what and how much is added and what temperature is chosen for the heat treatment, are very important.