Self-annihilation of antiphase boundaries in GaAs epilayers on Ge substrates grown by metal-organic vapor-phase epitaxy

The self-annihilation of antiphase boundaries (APBs) in GaAs epitaxial layers grown by low-pressure metal-organic vapor-phase epitaxy on Ge substrates is studied by several characterization techniques. Cross-sectional transmission electron microscopy shows that antiphase domain free GaAs growth on Ge was possible due to the proper selection of the growth parameters. The antiphase boundaries annihilate with each other after a thick 3 µm layer of GaAs growth on a Ge substrate as observed by scanning electron microscopy studies. Double crystal x-ray diffraction data shows a slight compression of GaAs on Ge, and the full width at half maximum decreases with increasing growth temperatures. This confirms that the APBs annihilate inside the GaAs epitaxial films. Low temperature photoluminescence measurements confirm the self-annihilation of the APBs at low temperature growth and the generation of APBs at higher growth temperatures