New developments in the heteroepitaxial growth of Be-chalcogenides based semiconducting alloys

We have studied the heteroepitaxial growth ofZn(Mg)BeSe alloys on both GaAs and Si substrates. X-ray measurements show that ZnMgBeSe quaternary alloys can be grown with a high structural quality on GaAs(001). Linewidths as lo w as to 20 arcsec have been obtained from double x-ray diffraction and the etch pit density is in the range of 10(-3) cm(-2). The growth of ZnBeSe ter nary alloys on vicinal Si(001) substrates has been investigated. Optical pr operties of Zn0.55Be0.45Se which is lattice-matched to silicon have been st udied by photoluminescence and reflectivity and a fundamental bandgap E-o o f 3.85 eV has been measured. Therefore, this material is a potential candid ate for ultraviolet B detection. However, it is important to note that thes e measurements are not conclusive about the direct nature of alloys bandgap s.