Investigation of nonequilibrium carrier transport in vanadium-doped CdTe and CdZnTe crystals using the time-resolved four-wave mixing technique
Language
en
Article de revue
This item was published in
Semiconductor Science & Technology. 2003, vol. 18, n° 4, p. 367-376
English Abstract
We present a novel way to determine the type of dominant carrier photoexcited from deep traps in a photorefractive semiconductor. A numerical analysis of a picosecond free-carrier grating dynamics has revealed an excitation ...Read more >
We present a novel way to determine the type of dominant carrier photoexcited from deep traps in a photorefractive semiconductor. A numerical analysis of a picosecond free-carrier grating dynamics has revealed an excitation intensity dependent grating diffusive decay time τD as well as effective carrier diffusion coefficient D, when the intensity varied in the range below that required to create a bipolar carrier plasma. According to the numerical analysis, an increase or decrease of effective diffusion coefficient D with excitation can be used as a criterion to distinguish the type of photogenerated carrier. We have verified this method experimentally by measuring dependences of effective D versus excitation density in a number of vanadium-doped and shallow-impurity codoped CdTe and ZnCdTe crystals, using for excitation a picosecond YAG:Nd laser (hν = 1.17 eV). The results were found to be in good agreement with predictions, based on carrier transport peculiarities in photorefractive crystals, and correlated well with the secondary ion mass spectroscopy data for each crystal.Read less <
English Keywords
Electric current carriers
Deep traps
Dopants
Four wave mixing
Simulation and Modeling
Photorefractive effect
Arsenic
Vanadium
Origin
Hal imported