X-ray reciprocal space mapping of strain relaxation in GaAs_1-xN_x on GaAs [100] by molecular-beam epitaxy

The effect of strain on GaAs_1-xN_x grown on GaAs is observed using two-dimensional [115] high-resolution x-ray diffraction rocking curves. The instance when the epilayer changes from a highly strained to a relaxed state, is captured and a change in peak profile is observed. The increase of growth rate is found to have an effect of maintaining the crystal quality and surface reconstruction. Interstitial N complex lowers the tensile strain due to its compressive nature, thereby increasing the critical thickness at high N%. We demonstrated that GaAs_0.952N_0.048 can be coherently grown to 100 nm on GaAs, exceeding the critical thickness by 4.7 times after an optimization of III–V–N growth by means of higher rf power compensation under an increased growth rate. © 2003 American Institute of Physics.