Characterization and applications of neutron-transmutation-doped germanium
Thermal-neutron irradiation of germanium leads to gallium acceptors, arsenic and selenium donors, as well as radiation defects. Unlike other neutron-transmutation-doped (NTD) semiconductors in which only donor impurities are introduced, NTD germanium contains both types of dopant impurities in the ratio of acceptor:donor = 3:1. Radiation defects and the evolution of each impurity as a function of time in NTD germanium were investigated by Hall-effect measurements and infrared absorption spectroscopy. The presence of radiation defects in an unannealed NTD germanium sample was clearly shown by measuring the net carrier concentration of annealed and unannealed samples as a function of time after neutron irradiation. Most of the radiation defects were removed by annealing above 400{degree}C for 1 hr. Using IR spectroscopy with band-edge light illumination, it was shown that transmutation-produced gallium acceptors were electrically active without annealing after NTD, while arsenic donors were not. Further evidence showed that group V donors in irradiated germanium formed complexes with vacancies. These complexes were formed between substitutional donors and vacancies as shown by IR spectroscopy on neutron-irradiated, phosphorus-doped germanium. It was concluded that vacancies diffuse to the substitutional donor sites to form complexes.
- Research Organization:
- California Univ., Berkeley, CA (USA)
- OSTI ID:
- 7072857
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360605* -- Materials-- Radiation Effects
ANNEALING
BARYONS
BEAMS
CHARGE CARRIERS
ELEMENTARY PARTICLES
ELEMENTS
FERMIONS
GERMANIUM
HADRONS
HALL EFFECT
HEAT TREATMENTS
HIGH TEMPERATURE
IMPURITIES
INFRARED SPECTRA
METALS
NEUTRON BEAMS
NEUTRONS
NUCLEON BEAMS
NUCLEONS
PARTICLE BEAMS
PHYSICAL RADIATION EFFECTS
RADIATION EFFECTS
SPECTRA
THERMAL NEUTRONS
TIME DEPENDENCE