Modeling of undercooling, nucleation, and multiple phase front formation in pulsed-laser-melted amorphous silicon

Journal Article · Tue Jan 01 04:00:00 EST 1985 · Mater. Res. Soc. Symp. Proc.; (United States)

OSTI ID:6947298

Wood, R F; Geist, G A; Solomon, A D; Lowndes, D H; Jellison, Jr, G E

Recently available experimental data indicate that the solidification of undercooled molten silicon prepared by pulsed laser melting of amorphous silicon is a complex process. Time-resolved reflectivity and electrical conductivity measurements provide information about near-surface melting and suggest the presence of buried molten layers. Transmission electron micrographs show the formation of both fine- and large-grained polycrystalline regions if the melt front does not penetrate through the amorphous layer. The authors have carried out extensive calculations using a newly developed computer program based on an enthalpy formulation of the heat conduction problem. The program provides the framework for a consistent treatment of the simultaneous formation of multiple states and phase-front propagation by allowing material in each finite-difference cell to melt, undercool, nucleate, and solidify under prescribed conditions. Calculations indicate possibilities for a wide variety of solidification behavior. The new model and selected results of calculations are discussed here and comparison with recent experimental data are made. 12 references, 7 figures.

• Research Organization: Oak Ridge National Lab., TN
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 6947298
• Journal Information: Mater. Res. Soc. Symp. Proc.; (United States), Journal Name: Mater. Res. Soc. Symp. Proc.; (United States) Vol. 35; ISSN MRSPD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602 -- Other Materials-- Structure & Phase Studies
360605* -- Materials-- Radiation Effects
AMORPHOUS STATE
DATA
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTROMAGNETIC RADIATION
ELEMENTS
HEAT FLOW
INFORMATION
LASER RADIATION
MELTING
NUCLEATION
NUMERICAL DATA
NUMERICAL SOLUTION
OPTICAL PROPERTIES
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
PHYSICAL RADIATION EFFECTS
RADIATION EFFECTS
RADIATIONS
REFLECTIVITY
SEMIMETALS
SILICON
SOLIDIFICATION
SURFACE PROPERTIES
TEMPERATURE DEPENDENCE
THEORETICAL DATA
TIME DEPENDENCE