Growth and characterization of beryllium-based II-VI compounds

We report on the growth and characterization of beryllium-chalcogenide laye rs prepared on GaAs (100) by molecular beam epitaxy. Be- and Te- terminated BeTe surfaces show (4 x 1) and (2 x 1) reconstructions, respectively. The stability of each surface is investigated by reflection high energy electro n diffraction as a function of substrate temperature. The dependence of gro wth rate of BeTe on growth temperature and Be cell temperature is investiga ted. The best full width at half maximum (FWHM) of a (400) x-ray rocking cu rve of BeTe is 78 arcsec. The dependence of the ZnBeSe energy gap on Be com position is obtained by four-crystal x-ray diffraction (XRD) and low temper ature photoluminescence measurements. The energy gap of Zn1-xBexSe varies a s E-g = 0.0107x + 2.790 (eV) for small Be composition (x < 0.25) at 77 K. L attice-matched ZnBeSe (E-g = 2.82 eV) and ZnMgBeSe (E-g = 2.975 eV) layers show narrower XRD peaks, the FWHM values of which are 64 and 21 arcsec, res pectively. The variation of FWHM of x-ray rocking curve due to lattice misf it is investigated for ZnMgBeSe quaternaries with various lattice misfits e xtending from compressive to tensile strain. The FWHM value under compressi ve strain increases more steeply with lattice misfit than that under tensil e strain. (C) 1999 American Institute of Physics. [S0021-8979(98)04123-1].