Epitaxial growth and large band-gap bowing of ZnSeO alloy

ZnSeO alloy was grown by molecular-beam epitaxy up to 1.3% O composition on GaAs substrate using rf plasma. The crystal structure of epitaxial ZnSeO alloy was zinc-blende. O composition was estimated by a strain-free lattice constant. No phase separation was observed by in situ reflection high-energy electron diffraction and x-ray diffraction. Photoluminescence intensity was larger than that of ZnSe. The peak energy shifted toward lower energies with increasing O composition. The band-gap energy determined by photoluminescence excitation spectra decreased with increasing O composition. A bowing parameter as high as 8 eV was obtained. This large band-gap bowing widens the controllable energy-gap range of II-VI semiconductor. (C) 2003 American Institute of Physics.