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HL: Fachverband Halbleiterphysik
HL 75: Poster IIIB
HL 75.22: Poster
Donnerstag, 19. März 2020, 15:00–17:30, P2/3OG
Identification of defect properties by positron annihilation in heavily doped n-type GaAs — •juanmei duan1,2, maciej oskar liedke1, manfred helm1,2, shengqiang zhou1, and slawomir prucnal1 — 1Helmholtz-Zentrum Dresden-Rossendorf, Institute of Ion Beam Physics and Materials Research, Bautzner Landstrasse 400, D-01328 Dresden, Germany — 2Technische Universität Dresden, D-01062 Dresden, Germany
The electron concentration limits for GaAs are a universal feature existing in group VI donors and Si doping, which limits the carrier concentration to 1e19 cm-3. In our work, we can use ion implantation method beyond the equilibrium solid solubility limits to achieve heavy doped GaAs with Zn, S and Te. We can use millisecond-range flash lamp annealing (FLA) or nanosecond-range pulsed laser annealing (PLA) to reactive and recrystallize the as-implanted samples. The carrier concentration for n-type GaAs can reach up to 5 e19 cm-3. , which is much above the solid solubility of S in GaAs (~1019 cm-3) prepared by MBE. From Positron annihilation spectroscopy (PAS) results, It shows the positron lifetime from heavily n-type doped GaAs has a longer lifetime (above 500ps) and lower intensity I2 than virgin GaAs, which indicates open-volume defects become bigger, defect evolving from monovacancy to multi-vacancy with decreasing the intensity after doping and annealing process.