Growth and conductive type control of ZnSe single crystals by vertical Bridgman method

A closed, double-crucible has been proved to be very successful for prevent ing the deviation from the stoichiometric compositions of the melt in the p rocess of ZnSe Bridgman growth, and to be necessary for preparing large twi n-free ZnSe single crystals. Under the optimized growth conditions, ZnSe cr ystals have been grown from the source materials with different composition ratio (Zn/Se) of 1.03-0.98. Photoluminescence spectra show that the I-1(d) ; I-2 and I-1 emissions are dominant for sample is with Zn/Se = 1, Zn/Se > 1, and Zn/Se < 1, respectively. The measurement of Hall effect and C-V char acteristics showed that the Zn/Se = 1 sample has a high resistivity, Zn/Se > 1 is low-resistivity, n-type, and Zn/Se < 1 is low-resistivity p-type. Th e highest carrier concentrations of n- and p-type ZnSe crystals are 8.8 x 1 0(17) cm(-3) and 1.8 x 10(17) cm(-3), respectively. These results show that low resistivity n- and p-type ZnSe single crystals can be successfully gro wn by changing the compositions of the starting materials. (C) 2001 Elsevie r Science B.V. All rights reserved.