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Nucleation Phenomena in Electron‐Hole Drop Formation in Ge and Si: I. Nucleation Rates
Author(s) -
Westervelt R. M.
Publication year - 1976
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2220740235
Subject(s) - nucleation , metastability , drop (telecommunication) , surface tension , breakup , phase diagram , thermodynamics , classical nucleation theory , radius , condensation , materials science , luminescence , condensed matter physics , chemistry , phase (matter) , physics , mechanics , telecommunications , computer security , organic chemistry , computer science , optoelectronics
A general nucleation theory for liquids possessing finite lifetimes, specifically for the condensation of electron‐hole drops (EHD) from a gas of free excitons (FE), is presented. The theory is developed for both homogeneous and inhomogeneous nucleation in Ge and Si. In Part I explicit expressions are derived for the steady‐state rates of formation J + and breakup J − of macroscopic EHD, and for the EHD size distribution in dynamic equilibrium. It is found that the FE‐EHD system above T ≈ 1.3 K in Ge is characterized by metastable states for which the equilibration time is extremely long. The expressions for J + and J − yield two sharp excitation thresholds. In Part II these results are applied to quantitatively predict for EHD the metastable time behavior, a procedure for measuring the surface tension, the phase diagram, and the EHD radius as a function of temperature. In Part III experimental luminescence data are presented for Ge which support this theory and accurately determine the surface tension.