Laser-Assisted Growth of ZnSe by Metalorganic Molecular Beam Epitaxy

ABSTRACTBy employing metalorganic molecular beam epitaxy (MOMBE), the heteroepitaxy of ZnSe on GaAs has been achieved using diethylselenium and diethylzinc. Significant (10x ∼ 15x) growth rate enhancement has been observed when radiation from an argon ion laser is incident to the surface; photons with energies greater than the bandgap at the growth temperature contribute to the enhancement. Photo-thermal effects are ruled out due to the low power densities used (∼200 mW/cm2). Growth rate enhancementis found to be a function of substrate temperature, VI/II gas flow ratio, laser wavelength and intensity. To further understand the effect of the laser on ZnSe growth, solid sources of Zn and Se are used in conjunction with metalorganic gas sources. The effect of laser illumination is found to depend on the combination of precursors employed: both growth rate enhancement and growth rate suppression are observed. Laser-assisted growth has application for achieving. selective area epitaxy and for tuning the surface stoichiometry.