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HL: Fachverband Halbleiterphysik
HL 64: Poster II
HL 64.50: Poster
Donnerstag, 19. März 2020, 10:00–13:00, P1A
Optically detected magnetic resonance spectroscopy of excitons in porous silicon and partially hydroxylated silicane — •Jonathan Zerhoch and Martin S. Brandt — Walter Schottky Institut and Physik-Department, Technische Universität München
Porous silicon and partially hydroxylated silicane, also known as siloxene, exhibit the strongest luminescence of any silicon-based material. We employ both continuous wave and pulsed optically detected magnetic resonance spectroscopy (ODMR) to study the recombination processes in these materials. In both, we observe a luminescence enhancing signature of the allowed Δ ms = ± 1 and the forbidden Δ ms = ± 2 transitions of triplet excitons and use the former to estimate their diameter. In addition, the resonance of dangling bond defects overlapping the triplet exciton signature and quenching the luminescence is observed. The technique of pulsed ODMR enables coherent control of the spin systems and, as expected, we find that the Δ ms = ± 1 transition of the triplet exhibits a Rabi frequency which is a factor of √2 higher than the Rabi frequency of the spin-1/2 dangling bond defect. The observed dipolar broadened Pake-doublet gives rise to a wide distribution of electron-hole distances that appears to suppress the observation of Rabi oscillations at the Δ ms = ± 2 resonance. Furthermore, we investigated the dynamical properties of the spin-1 and spin-1/2 systems providing T2 times and the timescales of the different recombination processes.