FORMATION OF CUPT-TYPE ORDERED (CD,ZN)TE AT CDTE ZNTE INTERFACE/

A CuPt-type ordered CdZnTe has been observed at CdTe/ZnTe interface se quentially grown by organometallic vapor-phase epitaxy on (001)GaAs at 400 degrees C. Selected area electron diffraction, cross-sectional hi gh-resolution electron microscopy, and computer image simulation have been employed to characterize the ordered structure in CdZnTe. Between CdTe and ZnTe, we observed a relatively uniform layer with dark contr ast band image by conventional transmission electron microscopy. Throu gh [110] projection, selected area electron diffraction pattern showed two sets of (1/2 1/2 1/2) extra spots with symmetrical intensity and corresponding high-resolution images showed doubling periodicity in co ntrast on {111} lattice planes. The ordered structure has been identif ied as CuPt-type ordered CdZnTe from electron diffraction, high-resolu tion images, and computer image calculations. Through [110] projection , it was observed that there were two variants for ordering according to each direction of doubling periodicity on {111} lattices planes, i. e., on (1(1) over bar 1) and on (<(1)over bar 11>). Each variant was o bserved to have its own domain structure of which size ranged from 10 to 20 nm and the two variants were observed with equal probability. (C ) 1998 Elsevier Science B.V. All rights reserved.