Carbon irradiated semi insulating GaAs for photoconductive terahertz pulse detection

Singh, Abhishek; Pal, S.; Surdi, Harshad; Prabhu, S. S.; Mathimalar, S.; Nanal, V.; Pillay, R. G.; Döhler, G. H.

doi:10.1364/oe.23.006656

Cited by 17 publications

(9 citation statements)

References 12 publications

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“…An alternative approach for short lifetime is to create point defects in SI-GaAs by ion-implantation technique. Arsenic, oxygen, nitrogen, carbon, hydrogen (proton), etc., have been implanted into SI-GaAs and the obtained GaAs PCAs are similar to those on LT-GaAs [8][9][10][11]. However, the process conditions for either LT-GaAs or ion-implanted GaAs are not easy to reproduce in mass production, because of the difficult control of low-temperature process for MBE [12,13], extremely high implantation energies ($MeV) for heavy ions [11] and the challenging control for post annealing at relatively low temperatures [8,14].…”

Section: Introductionmentioning

confidence: 95%

“…Thus, it is critical to find out a strategy of creating sufficient defects to reduce the carrier lifetime without affecting mobility detrimentally. High-energy and low-dosage ionimplantation has been verified to be an efficient method of creating proper profiles of defects, in order to obtain both excellent carrier acceleration at the shallow region and fast carrier trapping at the deep layer for THz generations [11,25]. Also, hydrogen implantation is extensively used to separate high-power active devices (IGBT, laser diodes, LED, etc.)…”

Section: Introductionmentioning

confidence: 99%

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Ion-Beam Modified Terahertz GaAs photoconductive antenna

Sun¹,

Zhang²

2019

Photodetectors [Working Title]

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Ion-implanted photoconductive GaAs terahertz (THz) antennas were demonstrated to deliver both high-efficiency and high-power THz emitters, which are attributed to excellent carrier acceleration and fast carrier trapping for THz generations by analyzing ultrafast carrier dynamics at subpicosecond scale. The implantation distance at over 2.5 μm is deep enough to make defects (Ga vacancies, As þ Ga …, etc.) quite few; hence, a few with good mobility similar to bare GaAs ensures excellent carrier acceleration in shallow distance <1.0 μm as photo carriers are generated by the pump laser. The implantation dosage is carefully optimized to make carrier trapping very fast, and screen effects by photo-generated carriers are significantly suppressed, which increases the THz radiation power of SI-GaAs antennas by two orders of magnitude. Under the same photoexcitation conditions (pump laser power, bias voltage), photocurrents from GaAs antennas with optimum conditions 300 keV, 5 Â 10 14 cm À2 for H implantation are decreased by two orders of magnitude; meanwhile, the THz radiation is enhanced by over four times, which means that the electrical-to-THz power conversion efficiency is improved by a factor of over 1600.

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Section: Introductionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Ion-Beam Modified Terahertz GaAs photoconductive antenna

Sun¹,

Zhang²

2019

Photodetectors [Working Title]

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“…The photocurrent signal is not a complete copy of the THz waveform, but presents a frequency filtering characteristic through conductivity [88]. Thus, materials with shorter carrier lifetimes (such as LT-GaAs and doped GaAs) are usually chosen to reduce the effect of conductivity on the results [89]. The carrier lifetime of LT-GaAs is shorter than 0.5 ps.…”

Section: Detection By Pcamentioning

confidence: 99%

Intense terahertz radiation: generation and application

Zhang

Zhao

2020

Front. Optoelectron.

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Strong terahertz (THz) radiation provides a powerful tool to manipulate and control complex condensed matter systems. This review provides an overview of progress in the generation, detection, and applications of intense THz radiation. The tabletop intense THz sources based on Ti:sapphire laser are reviewed, including photoconductive antennas (PCAs), optical rectification sources, plasma-based THz sources, and some novel techniques for THz generations, such as topological insulators, spintronic materials, and metasurfaces. The coherent THz detection methods are summarized, and their limitations for intense THz detection are analyzed. Applications of intense THz radiation are introduced, including applications in spectroscopy detection, nonlinear effects, and switching of coherent magnons. The review is concluded with a short perspective on the generation and applications of intense THz radiation.

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“…In order to reduce the cost of such THz systems, SI-GaAs is a promising option because it is cheaper than LT-GaAs and InGaAs, with the disadvantages of higher dark current and longer recombination times. Over the past times, technological efforts to improve the properties of this semiconductor have been explored, such as ion implantation [2], [3] or surface ablation using femtosecond laser [4].…”

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confidence: 99%

Influence of Laser Modulation Frequency on the Performance of Terahertz Photoconductive Switches on Semi-Insulating GaAs Exhibiting Negative Differential Conductance

Paz-Martínez

Treviño‐Palacios

Molina

et al. 2021

IEEE Trans. THz Sci. Technol.

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In typical terahertz time-domain spectroscopy systems, the use of the lock-in technique is necessary because of the low current induced at the receiver so that the laser pump beam must be modulated (chopped) at a frequency much lower than the laser repetition rate. This work shows that, in the case of semi-insulating GaAs (SI-GaAs) antennas, this modulation has an important effect on the antenna current and consequently, on the radiated electromagnetic pulse. There exists a threshold bias (whose value depends on the chopping frequency) where an abrupt increase in the current and consequently, in the terahertz emission takes place. The calculated energy of the pulse below and above the threshold shows that the energy doubles. The exact bias voltage at which this occurs changes with the laser modulation frequency when this is below 350 Hz, but at higher frequencies, the threshold remains almost constant. The experiments show that the responsibility for this behavior is the S-shape negative differential conductance exhibited by SI-GaAs originated by a slow field-enhanced charge trapping mechanism, which is also an important source of noise at the receiver of the system. Index Terms-Negative differential conductance (NDC), photoconductive switch, terahertz time-domain spectroscopy (THz-TDS). I. INTRODUCTIONO VER the past years, there has been an increase of new applications at terahertz (THz) frequencies for which Manuscript

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Carbon irradiated semi insulating GaAs for photoconductive terahertz pulse detection

Cited by 17 publications

References 12 publications

Ion-Beam Modified Terahertz GaAs photoconductive antenna

Ion-Beam Modified Terahertz GaAs photoconductive antenna

Intense terahertz radiation: generation and application

Influence of Laser Modulation Frequency on the Performance of Terahertz Photoconductive Switches on Semi-Insulating GaAs Exhibiting Negative Differential Conductance

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