@article{3048640, title = "The effect of arsenic overpressure on the structural properties GaAs grown at low temperature", author = "Lagadas, M and Hatzopoulos, Z and Tsagaraki, K and Calamiotou, M and and Lioutas, C and Christou, A", journal = "Journal of applied physics", year = "1996", volume = "80", number = "8", pages = "4377-4383", publisher = "AMER INST PHYSICS", issn = "0021-8979", doi = "10.1063/1.363396", abstract = "The structural properties of GaAs grown by molecular-beam epitaxy at low temperatures have been investigated by scanning electron microscopy, transmission electron microscopy, and high-resolution x-ray double-crystal rocking curves as a function of arsenic overpressure during growth. It was found that surface smoothness and excess arsenic incorporation both depend strongly on growth temperature and on As/Ga flux ratio, For each growth temperature there is a ‘’window” in the flux ratio which results in smooth surfaces. As-grown layers have an increased lattice constant in the growth direction. This relative lattice expansion increases with flux ratio at a constant growth temperature and eventually saturates, Transmission electron micrographs have revealed the presence of arsenic precipitates in material annealed at 600 degrees C. Increasing the As-4 pressure during growth results in increases in precipitate diameter by almost 50% while their density and shape remain constant. Based on these observations a model has been developed to explain the lattice expansion dependence on arsenic overpressure. (C) 1996 American institute of Physics." }