Trapping in Solids.
Abstract
A given impurity atom in a crystal may function as (1) an intensifier, (2) an activator, or (3) a killer of luminescence, or as (4) an electron trap, depending on the effective valence and location of the atom in the crystal. There is reason to believe that a given impurity atom, under certain circumstances, may perform two or more of these functions in time sequence without undergoing irreversible change. Some aspects of the role of traps in influencing cathodoluminescence efficiency of phosphors were investigated for six representative and extreme cases of phosphors with and without predominant trapping action. It was found that the exponential-decay (non-trapping) phosphors exhibit constantly decreasing efficiency with increasing temperature or excitation density, whereas power-law-decay (trapping) phosphors exhibit (a) increasing efficiency with increasing temperature, up to a temperature breakpoint, and (b) increasing or decreasing efficiency with increasing excitation density, according to whether the phosphor is excited at a temperature above or below the temperature breakpoint. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 12, 1948
- Accession Number
- AD0499815
Entities
People
- H. W. Leverenz
- S. Lasof
Organizations
- Sarnoff Corporation