GROWTH OF CADMIUM-SULFIDE SINGLE-CRYSTAL BY THE SUBLIMATION METHOD

A cadmium sulfide (CdS) single crystal was grown by the sublimation me thod without a seed crystal in a two-stage vertical electric furnace. The temperature difference, 15 degrees C, between the source and growt h parts in the growth tube was in good agreement with the calculated v alue of 14.7 degrees C. From the diffraction patterns, the single crys tal exhibits a hexagonal structure and its c-axis is along the symmetr y axis of the growth tube. The measured carrier concentration and mobi lity of the CdS single crystal are about 2.90 x 10(16) cm(-3) and 316 cm(2)/V . s, respectively, at room temperature. The energy bandgap obt ained from photocurrent measurements follows Varshni's equation E(g)(T ) = 2.552 eV - (5.75 x 10(-3) eV)T-2/(T + 3743) rather than a linear r elationship E(g)(T) = 2.58 eV - (5.24 x 10(-4) eV/K)T.