High crystalline quality ZnBeSe grown by molecular beam epitaxy with Be}Zn co-irradiation

High crystalline quality ZnBeSe epilayers with di!erent compositions were grown on GaAs substrates by molecular beam epitaxy using Be}Zn co-irradiation of the III}V surface and a ZnSe bu!er layer. A (1]2) re#ection high-energy electron di!raction pattern was formed after the Be}Zn co-irradiation indicating the formation of Be and Zn dimers on the GaAs surface. A two-dimensional growth mode was observed throughout the growth of the ZnSe bu!er layer and ZnBeSe epilayer. Narrow X-ray linewidth as low as 23 arcsec with the etch pit density of mid 104 cm~2 were obtained. The linewidth of the dominant excitonic emission is about 2.5 meV at 13 K for the near-lattice-matched ZnBeSe layer. For a nitrogen-doped sample, capacitance}voltage measurements showed a net acceptor concentration of 2.0]1017 cm~3. In addition, the use of a BeTe bu!er layer and of a Zn-irradiation with a ZnSe bu!er layer were also investigated. ( 2000 Elsevier Science B.V. All rights reserved. PACS: 81.15.Hi; 80.05.Dz; 78.55.Et; 61.10.Eq