The optical and structural properties of GaAs films grown at temperatu
res of between 460 and 690 degrees C on vicinal Si(110) substrates by
molecular-beam epitaxy are discussed and compared with the optical pro
perties of (110) GaAs with (100) GaAs. We have discussed the residual
strain and stress after annealing. The residual stress in films shifte
d the PL spectra to lower photon energies as the off-angle increased t
oward the [001] direction. The orientation dependence of the stress is
explainable by the mechanical properties of GaAs films. The thermal s
tress and strain of (110) GaAs were larger than those of (100) GaAs af
ter annealing. The thermal stress of GaAs on vicinal Si(110) tilted at
6 degrees toward the [001] direction increased from 3 x 10(9) to 4.1x
10(9) dyn/cm(2) after 1000 degrees C annealing.