REGROWTH OF QUANTUM-WELLS ON AN IN-SITU CL-2-ETCHED ALGAAS SURFACE BYMOLECULAR-BEAM EPITAXY

Regrowth of single quantum wells has been demonstrated on in-situ Cl-2 -etched hlGaAs surfaces by molecular beam epitaxy. The etched AlxGa1-x As (x=0.25) surface exhibited micro-roughness and recovered its specul ar smooth surface upon vacuum annealing at 600 degrees C as determined by reflection high-energy electron diffraction. Single quantum wells were grown on a series of AlGaAs buffer layers with thicknesses rangin g from 0 to 0.2 mu m on the etched and annealed AlGaAs surfaces. A 15- nm-thick quantum well grown on a 50-nm buffer layer showed a 4.4-meV p hotoluminescence full-width-at-half-maximum (FWHM), and a 10-nm quantu m well on a 0.1-mu m buffer layer presented a 2.3-meV FWHM when measur ed at 1.6 K. Secondary ion mass spectroscopy identified O, C, and Cl i mpurities at the unannealed regrowth interface. Upon annealing, the re sidual Cl was completely removed, and the O and the C contaminants wer e reduced over an order of magnitude to 5x10(13) and 9x10(11)/cm(2), r espectively.