Injection and temperature dependent carrier recombination rate and diffusion length in freestanding CVD diamond

We applied time‐resolved nonlinear optical techniques for investigation of carrier recombination and diffusion processes in a 420 μm thick CVD diamond, relatively free from structural and point defects. Injection of 1015–1017 cm−3 carrier density by two‐photon excitation and monitoring free carrier...

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Bibliographic Details
Published in:Physica status solidi. A, Applications and materials science Applications and materials science, 2013-10, Vol.210 (10), p.2016-2021
Main Authors: Ščajev, Patrik, Gudelis, Vytautas, Tallaire, Alexandre, Barjon, Julien, Jarašiūnas, Kęstutis
Format: Article
Language:English
Subjects:
Augers
Carrier density
carrier diffusion
Carrier recombination
diamond
Diamonds
Diffusion
Diffusion length
Excitons
free-carrier absorption
Genetic recombination
light-induced transient gratings
Materials science
Nonlinearity
recombination
Temperature
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Summary:We applied time‐resolved nonlinear optical techniques for investigation of carrier recombination and diffusion processes in a 420 μm thick CVD diamond, relatively free from structural and point defects. Injection of 1015–1017 cm−3 carrier density by two‐photon excitation and monitoring free carrier absorption decay in 80–800 K range provided lifetime of 720 ns at T ≥ 300 K. At low temperatures, a linear increase of the carrier recombination rate with the injection level was fitted by an effective bimolecular recombination coefficient B = 10−11–10−9 cm3 s−1 and attributed to the impact of excitons and biexcitons, contributing to phonon‐assisted indirect Auger recombination. At high temperatures, increase of recombination rate was governed by Coulomb enhanced direct Auger process with a 520 meV threshold. An ambipolar carrier mobility with its peak value of ∼1500 cm2 V−1 s−1 at room temperature was determined by transient grating technique at ∼2 × 1015 cm−3 excess carrier density. A strong decrease of mobility at higher injections revealed the role of carrier‐carrier scattering, exciton formation and bandgap renormalization. The simultaneous measurements of carrier lifetime and diffusivity provided carrier diffusion length, which varied in a 1–50 μm range, depending on injection and temperature.
ISSN:1862-6300
1862-6319
DOI:10.1002/pssa.201300045