No abstract

Strain relaxation in stripe-shaped GaAs layers on Si(100) substrates by post-growth patterning has been investigated by photoluminescence (PL) measurements. PL spectrum for the GaAs stripes along [001] showed peaks positioned at shorter wavelength than those for stripes along [011] and [01̄1]. The stripe-orientation dependence was regarded as the crystallographic anisotropy of strain relaxation in the stripe-shaped GaAs layers. The PL results, therefore, showed that the stripes along [001] were superior to those along [011] and [01̄1] for reducing residual strain in the GaAs layers.

Off-oriented Si (100) substrates had considerable influence on the crystallinity of a (Ca,Sr)F2 layer, which is lattice matched with GaAs and grown on the substrates by molecular beam epitaxy. The (Ca,Sr)F2 layer grown on the Si (100) substrate, off oriented toward 〈011〉, was not a single crystal but had a columnar structure. The (Ca,Sr)F2 layer grown on the exact Si (100) susbstrate, however, was a single crystal in which the crystallinity was quite good with a minimum channeling yield (χmin ) of the mixed fluoride layer in the Rutherford backscattering spectra of about 0.1. To obtain such good crystallinity, the temperature range was limited to around 500 °C. The influence of off-oriented substrates was opposite that found in GaAs/Si (100) structures.

No abstract

No abstract