Low-temperature-grown GaAs: Modeling of transient reflectivity experiments

Ortiz, V.; Nagle, J.; Lampin, Jean‐François; Péronne, Emmanuel; Alexandrou, Antigoni

doi:10.1063/1.2763971

Cited by 29 publications

(13 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Relative pump-induced variations of the Fresnel reflection coefficient ΔR/R are generally small enough (no more than a few percent) to be considered linearly dependent on the excess electron-hole pair density [30]. The analysis, however, is often complicated by contributions of several mechanisms that affect the total absorption change Δα(t) and its related real refractive index change Δn(t) [31,32]. Since the maximum of the ΔR/R signal varies almost linearly with the excitation pump power (from 1 mW to 10 mW), the hypothesis we made was that the transient differential reflectivity is more or less proportional to N ph (t) (which is either the number of photo-created electron-hole pairs due to band-to-band absorption or the number of free electrons in the conduction band due to absorption from deep levels).…”

Section: Results and Analysismentioning

confidence: 99%

Fabrication of high resistivity cold-implanted InGaAsP photoconductors for efficient pulsed terahertz devices

Fekecs¹,

Bernier²,

Morris³

et al. 2011

Opt. Mater. Express

View full text Add to dashboard Cite

A multiple-energy, high fluence, MeV Fe ion implantation process was applied at 83 K to heavily damage a low band gap (0.79 eV) epitaxial InGaAsP layer. Optimal rapid thermal annealing conditions were found and produced a fast photoconductor with high resistivity (up to 2500 Ω cm) and Hall mobility around 400 cm 2 V −1 s −1 . Short photocarrier trapping times (0.3 ps -3 ps) were observed via transient differential reflectivity measurements. Furthermore, photoconductive terahertz devices with coplanar electrodes were fabricated and validated. Under pulsed excitation with a 1550 nm femtosecond fiber laser source, antennas based on Fe-implanted InGaAsP are able to emit broadband radiation exceeding 2 THz. Given such specifications, this new material qualifies as a worthy candidate for an integration into optical terahertz spectrometer designs.

show abstract

Section: Results and Analysismentioning

confidence: 99%

Fabrication of high resistivity cold-implanted InGaAsP photoconductors for efficient pulsed terahertz devices

Fekecs¹,

Bernier²,

Morris³

et al. 2011

Opt. Mater. Express

View full text Add to dashboard Cite

show abstract

“…For most devices, the samples were fabricated without annealing [17], [18]. The lack of such process in the fabrication of the material results in low values of dark resistivity of the LT-GaAs and, subsequently, high values of dark current in the devices, as it is shown in Fig.…”

Section: Pca Prototypes Descriptionmentioning

confidence: 99%

Norton Equivalent Circuit for Pulsed Photoconductive Antennas—Part II: Experimental Validation

Garufo

Carluccio

Freeman

et al. 2018

IEEE Trans. Antennas Propagat.

View full text Add to dashboard Cite

This second part of two papers sequence presents the experimental validation of the Norton equivalent circuit model for pulsed photoconductive antennas provided in the first paper of the sequence. To this goal different prototypes of photoconductive antenna sources have been manufactured and assembled. The average powers radiated and their pertinent energy spectral densities have been measured. In order to obtain a validation of the original equivalent circuit proposed, an auxiliary electromagnetic analysis of the complete setup, including the quasi-optical link for the signals from the antenna feeds to the detectors had to be developed. By using the combined theoretical model (circuit and quasi-optics), an excellent agreement is achieved between the measured power and the power estimated. This agreement fully validates the circuit model, which can now be used to design new photoconductive antennas, including optical and electrical features of the semiconductor materials, as well as the details of the antenna gaps and the purely quasi-optical components.

show abstract

“…To describe the carrier dynamics in SI GaAs, we used the SRHM including thermal processes following Ortiz et al 19 The rate equations concern an electron density in the conduction band n, hole density in the valence band p, and neutral EL2 density n DD . Since the SRH recombination is dominant in the SI GaAs material, the band-to-band irradiative recombination term is neglected, as well as Auger recombination.…”

Section: The Srhm and Its Simplificationmentioning

confidence: 99%

“…In the above equations, h␥ is a single photon energy at a wavelength of 1064 nm, ␣ is the absorption coefficient, which is dependent on the neutral EL2 concentrations, 19 ␤ CB-DD is the electronto-donor capture coefficient, ␤ VB-DD is the hole capture coefficient, and ␤ DD-CB th and ␤ DD-VB th are the thermally activated detrapping coefficients, which read…”

Section: The Srhm and Its Simplificationmentioning

confidence: 99%

See 1 more Smart Citation

Photoresistances of semi-insulating GaAs photoconductive switch illuminated by 1.064 μm laser pulse

Zheng

Ruan³

et al. 2009

Journal of Applied Physics

View full text Add to dashboard Cite

The Shockley-Read-Hall model ͑SRHM͒ and its simplified model ͑SSRHM͒ were used to describe the characteristics of a photoconductive semiconductor switch ͑PCSS͒ made from a semi-insulating ͑SI͒ gallium arsenide ͑GaAs͒ chip, biased at low voltage, and illuminated by a 1.064 m laser pulse. These characteristics include the free carrier densities, dynamic photoresistance, and time evolution of output pulses of the PCSS. The deep donor EL2 centers in SI GaAs play a dominant role in both the SRHM and SSRHM as electrons at EL2 unionized centers are strongly excited by the subband-gap photons at the wavelength of 1.064 m. Theoretical modeling on the evolution of the experimental measured output pulses led to a two-step micromechanism of electron excitation process within the GaAs chip. The minimum photoresistances predicted by the SSRHM are in good agreement with experimental measurements, which confirms the dominant role of EL2 in the generation of electric pulses from a SI GaAs photoconductivity switch on which the 1064 nm laser pulse is illuminated.

show abstract

Low-temperature-grown GaAs: Modeling of transient reflectivity experiments

Cited by 29 publications

References 30 publications

Fabrication of high resistivity cold-implanted InGaAsP photoconductors for efficient pulsed terahertz devices

Fabrication of high resistivity cold-implanted InGaAsP photoconductors for efficient pulsed terahertz devices

Norton Equivalent Circuit for Pulsed Photoconductive Antennas—Part II: Experimental Validation

Photoresistances of semi-insulating GaAs photoconductive switch illuminated by 1.064 μm laser pulse

Contact Info

Product

Resources

About