GaSe crystals with antireflection coatings for terahertz generation

Redkin, R. A.; Kobtsev, D. A.; Bereznaya, S. A.; Korotchenko, Z. V.; Sarkisov, Yu. S.; Mihaylov, T.; Sarkisov, S. Yu.

doi:10.1088/2053-1591/ab5318

Cited by 12 publications

(4 citation statements)

References 26 publications

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“…The second pulse was divided using another beam splitter (BS2). The more intense pulse (97% of power) extracted at BS2 passed through an SR-541 chopper (Standford Research, Sunnyvale, CA, USA) and was focused onto a GaSe crystal to generate a terahertz pulse via optical rectification [22,23]. Another pulse (3% of power) was directed to the delay line DL2 and then to a ZnTe electrooptical crystal for terahertz pulse detection.…”

Section: Optical Pump-terahertz Probe Measurementsmentioning

confidence: 99%

Electrical Relaxation and Transport Properties of ZnGeP2 and 4H-SiC Crystals Measured with Terahertz Spectroscopy

et al. 2023

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Terahertz photoconductivity and charge carrier recombination dynamics at two-photon (ZnGeP2) and three-photon (4H-SiC) excitation were studied. Thermally annealed, high-energy electron-irradiated and Sc-doped ZnGeP2 crystals were tested. The terahertz charge carrier mobilities were extracted from both the differential terahertz transmission at a specified photoexcitation condition and the Drude–Smith fitting of the photoconductivity spectra. The determined terahertz charge carrier mobility values are ~453 cm2/V·s for 4H-SiC and ~37 cm2/V·s for ZnGeP2 crystals. The charge carrier lifetimes and the contributions from various recombination mechanisms were determined at different injection levels using the model, which takes into account the influence of bulk and surface Shockley–Read–Hall (SRH) recombination, interband radiative transitions and interband and trap-assisted Auger recombination. It was found that ZnGeP2 possesses short charge carrier lifetimes (a~0.01 ps−1, b~6 × 10−19 cm3·ps−1 and c~7 × 10−40 cm6·ps−1) compared with 4H-SiC (a~0.001 ps−1, b~3 × 10−18 cm3·ps−1 and c~2 × 10−36 cm6·ps−1), i.e., τ~100 ps and τ~1 ns at the limit of relatively low injection, when the contribution from Auger and interband radiative recombination is small. The thermal annealing of as-grown ZnGeP2 crystals and the electron irradiation reduced the charge carrier lifetime, while their doping with 0.01 mass % of Sc increased the charger carrier lifetime and reduced mobility. It was found that the dark terahertz complex conductivity of the measured crystals is not fitted by the Drude–Smith model with reasonable parameters, while their terahertz photoconductivity can be fitted with acceptable accuracy.

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Section: Optical Pump-terahertz Probe Measurementsmentioning

confidence: 99%

Electrical Relaxation and Transport Properties of ZnGeP2 and 4H-SiC Crystals Measured with Terahertz Spectroscopy

et al. 2023

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“…Up to now, anti-reflection coating of GaSe was demonstrated in [151] for 800-nm wavelength with magnetron sputtering of SiO 2 and SiO 2 /Si 3 N 4 layers, leading to a higher THz generation efficiency, as less driving pulse power is reflected off the front surface. Furthermore, [152,153] show that the fabrication of anti-reflection micro-structures can be used to increase the MIR transmission of GaSe crystals.…”

Section: Multiple Reflections From Gasementioning

confidence: 99%

Detection Efficiency and Bandwidth Optimized Electro-Optic Sampling of Mid-Infrared Waves

Höfer

2022

Springer Theses

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“…The second one was divided by another beam splitter (BS2). The more intense pulse (97% of power) extracted at BS2 passed through a SR-541 chopper (Standford Research, Sunnyvale, CA, USA) and was focused onto a GaSe crystal to generate a terahertz pulse by optical rectification [19,20]. Another pulse (3% of power) was directed to the delay line DL2 and then to a ZnTe electro-optical crystal for terahertz pulse detection.…”

Section: Optical Pump-terahertz Probe Setupmentioning

confidence: 99%

Optical Pump–Terahertz Probe Study of HR GaAs:Cr and SI GaAs:EL2 Structures with Long Charge Carrier Lifetimes

et al. 2021

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The time dynamics of nonequilibrium charge carrier relaxation processes in SI GaAs:EL2 (semi-insulating gallium arsenide compensated with EL2 centers) and HR GaAs:Cr (high-resistive gallium arsenide compensated with chromium) were studied by the optical pump–terahertz probe technique. Charge carrier lifetimes and contributions from various recombination mechanisms were determined at different injection levels using the model, which takes into account the influence of surface and volume Shockley–Read–Hall (SRH) recombination, interband radiative transitions and interband and trap-assisted Auger recombination. It was found that, in most cases for HR GaAs:Cr and SI GaAs:EL2, Auger recombination mechanisms make the largest contribution to the recombination rate of nonequilibrium charge carriers at injection levels above ~(0.5–3)·1018 cm−3, typical of pump–probe experiments. At a lower photogenerated charge carrier concentration, the SRH recombination prevails. The derived charge carrier lifetimes, due to the SRH recombination, are approximately 1.5 and 25 ns in HR GaAs:Cr and SI GaAs:EL2, respectively. These values are closer to but still lower than the values determined by photoluminescence decay or charge collection efficiency measurements at low injection levels. The obtained results indicate the importance of a proper experimental data analysis when applying terahertz time-resolved spectroscopy to the determination of charge carrier lifetimes in semiconductor crystals intended for the fabrication of devices working at lower injection levels than those at measurements by the optical pump–terahertz probe technique. It was found that the charge carrier lifetime in HR GaAs:Cr is lower than that in SI GaAs:EL2 at injection levels > 1016 cm−3.

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GaSe crystals with antireflection coatings for terahertz generation

Cited by 12 publications

References 26 publications

Electrical Relaxation and Transport Properties of ZnGeP2 and 4H-SiC Crystals Measured with Terahertz Spectroscopy

Electrical Relaxation and Transport Properties of ZnGeP2 and 4H-SiC Crystals Measured with Terahertz Spectroscopy

Detection Efficiency and Bandwidth Optimized Electro-Optic Sampling of Mid-Infrared Waves

Optical Pump–Terahertz Probe Study of HR GaAs:Cr and SI GaAs:EL2 Structures with Long Charge Carrier Lifetimes

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