This letter reports a dramatic improvement in crystalline quality of AlAs0.16Sb0.84 ordered alloys compared with random ones grown by modulated molecular-beam epitaxy (MMBE) on InAs substrates. The average As/Sb ratio in these ordered alloys is accurately controlled by the modulation of As2 and Sb2 beams. The surface morphology of the epilayers is mirrorlike to the naked eye and appears texture- and cluster-free under an electron scanning microscope. X-ray diffraction measurements reveal that the lattice-matched conditions for AlAsxSb1-x epilayers to InAs can be easily achieved by simply changing the As-shutter dutycycle. Distinct satellite peaks corresponding to the ordered structure with a period of about 11 Å are also clearly observed. Strong photoluminescence (PL) is observed from GaAs0.08Sb0.92/AlAs 0.16Sb0.84 single quantum well structures up to room temperature under a very low photoexcitation (5 W/cm2). At 5 K the PL linewidth is 4.5 meV.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)