Vapour growth of bulk ZnSe single crystals

Large, partly faceted ZnSe single crystals have been grown in the closed tu be system by the unseeded sublimation travelling heater method (STHM) at 11 00 degrees C and undercooling Delta T less than 10 degrees C. As-grown crys tals are highly transparent and have very good optical homogeneity by sight . High quality of the crystals was confirmed by double crystal X-ray diffra ction which showed the full-width at half-maximum (FWHM) of the rocking cur ves to be less than 20 arcsec on the (2 2 0) ZnSe diffraction planes of the crystals. Selective chemical etching showed a dislocation density of these faces to be less than 5 x 10(4) cm(-2). The room-temperature photoluminesc ence (PL) spectrum under pulse excitation consists of only one near-band-ed ge line. Free and bound exciton as well as donor-acceptor pair recombinatio n are observable at 13 K. (C) 1999 Elsevier Science B.V. All rights reserve d.