Laser-modified molecular beam epitaxial growth of (Al)GaAs on GaAs and (Ca,Sr)F2/GaAs substrates

We report results on the effect of a 193 nm ArF excimer laser on molecular beam epitaxial growth of (Al)GaAs on GaAs substrates and GaAs on lattice-matched (Ca,Sr)F2/GaAs heterostructures. For growth on GaAs substrates, regions exposed to the laser show photoluminescence and excellent channeling as determined by Rutherford backscattering spectroscopy, whereas regions outside the laser show no photoluminescence. For growth on (Ca,Sr)F2 surfaces, laser irradiation inhibits the growth of GaAs for fluences above a critical value of 0.12 J/cm2 pulse because of laser-induced desorption of absorbed Ga atoms, which are relatively weakly bound to (Ca,Sr)F2, compared to GaAs surfaces.