Optical Studies of Radiation Damage Processes.
Abstract
A research program using the high dose rates available from an electron linear accelerator and fast optical techniques to study excitation-deexcitation, trapping, and radiation damage processes is presented. Radiation damage rates in gallium arsenide noncoherent and laser p-n junction diodes are compared by measuring the electrical characteristics and the electroluminescence output before and after irriation with fast electrons. A nonthermal, electrical annealing process is described which is effective in restoring the optical properties of irradiated diodes; the electrical characteristics, which are damaged by the radiation, are not restored by the anneal. To account for the various observations, a model is proposed in which the radiation does not introduce additional nonradiative recombination centers as previously thought but changes the radiative recombination centers to nonradiative. Potassium chloride is also investigated, and the shift in the peak absorption of the F-center with temperature is used to compute effective lattice frequencies. The self-bleaching of the F-centers and the energy required to form an F-center by ionization is experimentally determined as a function of initial F-center concentration and as a function of temperature. A value of 40 eV/F-center is measured at 300K at times of the order of microseconds after a radiation pulse; measurements a few seconds after the pulse yield a higher value due to the self-bleaching of the centers. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1970
- Accession Number
- AD0715305
Entities
People
- Rodolfo A. Cesena
- Terry M. Flanagan
- Victor A. J. Van Lint