Real-time studies of gallium adsorption and desorption kinetics on sapphire (0001) by grazing incidence small-angle x-ray scattering and x-ray fluorescence

Journal Article · Thu May 15 04:00:00 EDT 2008 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.2936969· OSTI ID:21137271

Yiyi, Wang; Oezcan, Ahmet S; Ludwig, Karl F ^[1]; Bhattacharyya, Anirban ^[2]

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1. Physics Department, Boston University, Boston, Massachusetts 02215 (United States)
2. Department of Electrical and Computer Engineering, Boston University, Boston, Massachusetts 02215 (United States)

Gallium adsorption and desorption on c-plane sapphire has been studied by real-time grazing incidence small-angle x-ray scattering and x-ray fluorescence as a function of substrate temperature (680-740 deg. C) and Ga flux. The x-ray techniques monitor the surface morphology evolution and amount of Ga on the surface. During deposition, nanodroplets of liquid Ga are observed to form on the surface and coarsen. The growth of droplet size during continuous deposition follows dynamical scaling, in agreement with expectations from theory and simulations which include deposition-induced droplet coalescence. However, observation of continued droplet distance scale coarsening during desorption points to the necessity of including further physical processes in the modeling. The desorption rate at different substrate temperatures gives the activation energy of Ga desorption as 2.7 eV, comparable to measured activation energies for desorption from Ga droplets on other substrates and to the Ga heat of vaporization.

• OSTI ID: 21137271
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 10 Vol. 103; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ACTIVATION ENERGY
ADSORPTION
COALESCENCE
DEPOSITION
DESORPTION
DROPLETS
FLUORESCENCE
GALLIUM
LIQUID METALS
MORPHOLOGY
NANOSTRUCTURES
SAPPHIRE
SIMULATION
SMALL ANGLE SCATTERING
SUBSTRATES
VAPORIZATION HEAT
X-RAY DIFFRACTION
X-RAY FLUORESCENCE ANALYSIS