Evaluation of photoelectric processes in photorefractive crystals via the exposure characteristics of light diffraction

Kadys, A.; Gudelis, V.; Sūdžius, M.; Jarašiūnas, K.

doi:10.1088/0953-8984/17/1/004

Cited by 5 publications

(3 citation statements)

References 22 publications

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“…We note that similar values of S and B fitted well the FWM kinetics in the nominally undoped epilayer. Carrier generation and recombination rates under different photoexcitation conditions can be revealed by measuring the dependence of diffraction efficiency η as a function of the excitation intensity I 0 [25]. Linear carrier generation dominated in all samples and resulted in a quadratic increase of η versus I 0 at t = 0 ps (see figure 8).…”

Section: Numerical Modellingmentioning

confidence: 99%

The determination of high-density carrier plasma parameters in epitaxial layers, semi-insulating and heavily doped crystals of 4H-SiC by a picosecond four-wave mixing technique

Neimontas¹,

Malinauskas²,

Aleksiejūnas³

et al. 2006

Semicond. Sci. Technol.

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We applied a picosecond four-wave mixing technique for measurements of carrier lifetimes and diffusion coefficients in highly excited epitaxial layers, semi-insulating and heavily doped 4H-SiC substrates. Optical carrier injection at two different wavelengths (266 and 355 nm) allowed us to vary the depth of the excited region from 1-2 µm to 50 µm, and thus determine photoelectric parameters of carrier plasma in the density range from 2 × 10 16 to 10 19 cm −3 . Strong dependence of carrier lifetime and mobility on carrier density was found in the epitaxial layers. The origin of fast decay components, not resolved previously by photoluminescence and free-carrier absorption techniques in SiC, was attributed to nonlinear carrier recombination. Numerical modelling provided a value of bimolecular recombination coefficient equal to B = (2-4) × 10 −11 cm 3 s −1 and verified a surface recombination velocity S = 4 × 10 4 cm s −1 . In heavily doped crystals, nonlinear carrier recombination reduced the carrier lifetime down to 1.1 ns, while in semi-insulating ones a lifetime of 1.5-2.5 ns was measured. Temperature dependences of four-wave mixing provided monopolar carrier mobility in heavily doped and bipolar one in semi-insulating crystals, and revealed the contribution of ionized impurity and phonon scattering mechanisms.

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Section: Numerical Modellingmentioning

confidence: 99%

The determination of high-density carrier plasma parameters in epitaxial layers, semi-insulating and heavily doped crystals of 4H-SiC by a picosecond four-wave mixing technique

Neimontas¹,

Malinauskas²,

Aleksiejūnas³

et al. 2006

Semicond. Sci. Technol.

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show abstract

“…η us a function I 0 ) were shown to be informative for the characterization of carrier generation mechanisms at different excitations. 16,17 For relatively low efficiencies (η<10%), EC follows the power dependence. Assuming that the carrier concentration increases with excitation as N ∝ I k and diffraction signal is proportional to concentrations squared η FC ∝ (N) 2 , the diffraction efficiency can be expressed as η ∝ I 2k .…”

Section: Results and Discutionmentioning

confidence: 99%

“…The increased γ value towards longer delays is related to the non-linear grating decay character, because the linear decay does not change γ values with ∆t. 17 The numerically calculated EC at ∆t = 0 and 1.5 ns are shown in Fig. 3 b.…”

Section: Results and Discutionmentioning

confidence: 99%

<title>Deeper insight into non-equilibrium carrier dynamics in InP:Fe: experimental and modeling</title>

et al. 2006

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Non-equilibrium carrier generation, transport, and recombination have been investigated in Fe-doped InP crystals experimentally in subnanosecond time domain by using time-resolved picosecond four-wave mixing technique. The carriers were generated by below band-gap excitation at 1064 nm (hν = 1.17 eV), what allowed photoexcitation of nonequilibrium carriers from/via Fe-related deep levels. The contributions of Fe 2+ /Fe 3+ deep level states and of the excited state Fe 2+* have been analyzed by numerical modeling, using the relevant model which took into account carrier generation via different defect states, as well recombination and diffusion. The modeling was helpful to get insight into varying with excitation generation rates of holes and electrons and explained the main features of FWM kinetics and exposure characteristics.

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Nondestructive evaluation of differently doped InP wafers by time-resolved four-wave mixing technique

Kadys

Sūdžius

Jarašiūnas

et al. 2006

Materials Science and Engineering: B

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Evaluation of photoelectric processes in photorefractive crystals via the exposure characteristics of light diffraction

Cited by 5 publications

References 22 publications

The determination of high-density carrier plasma parameters in epitaxial layers, semi-insulating and heavily doped crystals of 4H-SiC by a picosecond four-wave mixing technique

The determination of high-density carrier plasma parameters in epitaxial layers, semi-insulating and heavily doped crystals of 4H-SiC by a picosecond four-wave mixing technique

<title>Deeper insight into non-equilibrium carrier dynamics in InP:Fe: experimental and modeling</title>

Nondestructive evaluation of differently doped InP wafers by time-resolved four-wave mixing technique

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