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 laye rs grown by low-pressure metal-organic vapor-phase epitaxy on Ge substrates is studied by several characterization techniques. Cross-sectional transmi ssion electron microscopy shows that antiphase domain free GaAs growth on G e was possible due to the proper selection of the growth parameters. The an tiphase boundaries annihilate with each other after a thick 3 mum layer of GaAs growth on a Ge substrate as observed by scanning electron microscopy s tudies. Double crystal x-ray diffraction data shows a slight compression of GaAs on Ge, and the full width at half maximum decreases with increasing g rowth 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. (C) 2001 American Institute of Phys ics.