Surface diffusion of Sb on Ge(111) investigated by second harmonic microscopy

Miscellaneous · Wed Jan 01 00:00:00 EST 1992

OSTI ID:5528204

Schultz, K A

Surface diffusion of Sb on Ge(111) has been measured with the newly-developed technique of second harmonic microscopy. In this method, concentration profiles at submonolayer coverage are imaged directly by second harmonic generation with 5 [mu]m spatial resolution. A Boltzmann-Matano analysis of the concentration profiles yields the coverage dependence of the diffusivity D without parameterization. Experiments were performed at roughly 70% of the bulk melting temperature T[sub m]. In the coverage range of 0 < [theta] < 0.6, the activation energy E[sub diff] remains constant at 47.5 [+-] 1.5 kcal/mol. The corresponding pre-exponential factor decreases from 8.7 [times] 10[sup 3[+-]0.4] to 1.6 [times] 10[sup 2[+-]0.4] cm[sup 2]/sec. The results are explained in terms of a new vacancy model for surface diffusion at high-temperatures. The model accounts semiquantitatively for the large values of E[sub diff] and D[sub o], and suggest that these quantities may be manipulated by bulk doping levels and photon illumination of the surface.

• Research Organization: Illinois Univ., Urbana, IL (United States)
• OSTI ID: 5528204
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANTIMONY
DIFFUSION
GERMANIUM
CRYSTAL DOPING
HARMONIC GENERATION
SURFACE PROPERTIES
MICROSCOPY
VACANCIES
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
ELEMENTS
FREQUENCY MIXING
METALS
POINT DEFECTS
360601* - Other Materials- Preparation &amp; Manufacture
665000 - Physics of Condensed Matter- (1992-)