EPITAXIAL-GROWTH OF CUINSE2 SINGLE-CRYSTAL BY HALOGEN TRANSPORT METHOD

CuInSe2 single crystals were epitaxially grown on (001) GaP, (001) GaA s, and (110) GaP by the halogen transport Method. The orientation rela tionships in the growth on the (001) and (110) faces were (a) [001]CuI nSc2 parallel-to [001]sub and [100]CuInSe2 parallel-to [100]sub (c-axi s orientation growth), and (b) [110]CuInSe2 parallel-to [110]sub and [ 001]CuInSe2 parallel-to [001]sub, respectively. On (001) InP, the orie ntation relationships between the layer and substrate consist of two s ets: (c) [100]CuInSe2 parallel-to [001]sub and [001]CuInSe2 parallel-t o [010]sub, and (d) [100]CuInSe2 parallel-to [001]sub and [001]CuInSe2 parallel-to [100BAR]sub (a-axis orientation growth). The above result s, i.e., c-axis growth on (001) GaP and (001) GaAs and a-axis growth o n (001) InP, could be explained by a criterion of the minimum lattice mismatch between grown layers and substrates. A series of growth exper iments on (001) GaAs indicated that appropriate gas etching of the sub strate surface and growth temperature were required for obtaining twin -free single-crystal epitaxial CuInSe2.