Fabrication and characterization of III–V semiconductor superlattices with sinusoidal compositional modulation

We fabricated semiconductor superlattices of GaAs1−xSbx in which the chemical composition x varies sinusoidally along the direction of growth. This was accomplished by means of a novel molecular-beam epitaxy growth technique, in which the periodic modulation is achieved by substrate rotation in the presence of non-uniform flux distributions of elemental sources, rather than by shutter openings and closings. The sinusoidal nature of the compositional profiles of GaAs1−xSbx was inferred from the presence of only a single superlattice Fourier component in the X-ray diffraction spectra observed on these novel structures. Superlattice formation by this method is additionally supported by systematic photoluminescence data.