A comprehensive study of ultrafast carrier dynamics of LT-GaAs: Above and below bandgap regions

Vashistha, Nikita; Kumar, Mahesh; Singh, Rajiv Kumar; Panda, Debiprasad; Tyagi, Lavi; Chakrabarti, Subhananda

doi:10.1016/j.physb.2020.412441

Cited by 14 publications

(18 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The details of the ultrafast setup are similar to and can be found in our previous work. 18 The integrated process is given in Scheme 1.…”

Section: Methodsmentioning

confidence: 99%

“…This broadband photo-induced absorption in the NIR region is due to the excited-state free charge carrier density in the conduction band. 57 The relaxation kinetics shows an exponential decay which is numerically fitted using the equation, 18 as shown in Table S2, Supporting Information, and the details are mentioned in the Supporting Information. The detailed comparative relaxation mechanism is discussed later.…”

Section: Ultrafast Transient Response Of Fifth-annealed Nps On N + Gaasmentioning

confidence: 99%

“…56 Ultrafast investigation reveals enhanced absorption for optical excitation resonant with band gap. 18,57 Various studies have reported the annealing-induced lifetime reduction from nanoseconds to picosecond and sub-picosecond levels. 18,58,59 A comprehensive analysis of stepped annealingbased AuGe NPs on GaAs is presented here, which has close similarities in terms of annealing recipe and procedure.…”

Section: Ultrafast Transient Response Of Fifth-annealed Nps On N + Gaasmentioning

confidence: 99%

“…The experimental findings discussed above are found in proximity with one of the plasmon decay phenomena called plasmon-induced interfacial charge−transfer transition (PICTT), an optical phenomenon occurring at metal−semiconductor interfaces. 18,57 The peak absorption is also subjected to the density of states; the kinetics shown in Figure 9d are compared for a wavelength of about 840 nm (GaAs having only three kinetics and showed peak absorption at about 850 nm) that lies around the band edge of the conduction band.…”

Section: Ultrafast Transient Response Of Fifth-annealed Nps On N + Gaasmentioning

confidence: 99%

See 3 more Smart Citations

Tuning the Plasmonic Response of AuGe Nanoparticles on GaAs Substrates: Implications for Photodetectors

Tyagi

Kumar

Paul

et al. 2021

ACS Appl. Nano Mater.

Self Cite

View full text Add to dashboard Cite

We present an integral study on the photonic response of AuGe nanoparticles (NPs) to establish a correlation between different parameters such as NP size, volume, and distribution over different substrates (n + GaAs, semiconducting GaAs) having different film thicknesses (∼5, ∼10 nm) at different annealing temperatures (573 and 673 K) subjected to repeated and stepped annealing cycles. The structural characterization of overlayer growth and formation of AuGe nanoclusters/ NPs is correlated with unusual plasmonic response measured during photonic characterization. The morphological changes induced by stepped annealing of the AuGe/GaAs system resulted in enhanced light emission and favorable tuning of plasmon frequency. A larger photoluminescence enhancement is measured with the fifth anneal, which is found to be related to the enhanced NP reflectance and is in good theoretical agreement with the Drude−Lorentz model. The numerical negative real permittivity "ε 1 " confirms the plasmonic impact, while X-ray photoelectron spectroscopy studies reveal the unique intermixing phenomena of AuGe and GaAs at the interface due to annealing. Additionally, ultrafast studies depict the periodic absorbance in the below-band-gap region of GaAs resembling an EL2-state-like behavior. The AuGe NPs embedded/adhered on a light-emitting surface thus offer both the ease and flexibility for tuning the plasmon resonance frequency, to attain tweaked and enhanced light-matter coupling, which can be concluded as plasmon-induced interfacial charge-transfer transition phenomena. The enhanced light coupling enhances both the photovoltaic conversion efficiency and quantum efficiency, thereby enabling increased solar cell fill factor and responsivity enhancement in photovoltaic devices such as photodetectors and thermal imagers.

show abstract

“…The details of the ultrafast setup are similar to and can be found in our previous work. 18 The integrated process is given in Scheme 1.…”

Section: Methodsmentioning

confidence: 99%

Section: Ultrafast Transient Response Of Fifth-annealed Nps On N + Gaasmentioning

confidence: 99%

Section: Ultrafast Transient Response Of Fifth-annealed Nps On N + Gaasmentioning

confidence: 99%

Section: Ultrafast Transient Response Of Fifth-annealed Nps On N + Gaasmentioning

confidence: 99%

See 2 more Smart Citations

Tuning the Plasmonic Response of AuGe Nanoparticles on GaAs Substrates: Implications for Photodetectors

Tyagi

Kumar

Paul

et al. 2021

ACS Appl. Nano Mater.

Self Cite

View full text Add to dashboard Cite

show abstract

“…This mechanism has been proposed in a similar system LT-GaAs. [39,40] More systematical studies using tunable excitation wavelengths can further distinguish the relaxation mechanisms. The appearance of a plateau-like slow relaxation may correspond to the trap emptying time or recombination time.…”

Section: Wwwadvopticalmatdementioning

confidence: 99%

1550 nm Compatible Ultrafast Photoconductive Material Based on a GaAs/ErAs/GaAs Heterostructure

Zhang

Ren

et al. 2021

Advanced Optical Materials

View full text Add to dashboard Cite

The sub‐bandgap absorption and ultrafast relaxation in a GaAs/ErAs/GaAs heterostructure are reported. The infrared absorption and 1550 nm‐excited ultrafast photo‐response are studied by Fourier transform infrared spectrometry and time‐domain pump–probe technique. The two absorption peaks located at 2.0 (0.62 eV) and 2.7 µm (0.45 eV) are originated from the ErAs/GaAs interfacial Schottky states and the ErAs itself, respectively. The photo‐excited carrier lifetime, excited using 1550 nm light, is measured to be as low as 190 fs for the GaAs/ErAs/GaAs heterostructure, making it a promising material for 1550‐nm‐technology‐compatible, high critical‐breakdown‐field THz devices. The relaxation mechanism is proposed and the functionality of ErAs is revealed.

show abstract

Terahertz Detection Using Enhanced Two‐Step Absorption in Photoconductive Metasurfaces Gated at λ = 1.55 µm

Jung

Hale

Briscoe

et al. 2022

Advanced Optical Materials

View full text Add to dashboard Cite

Superior ultrafast photoconductive properties make low temperature grown (LT) GaAs one of the best materials for photoconductive terahertz (THz) detection. However, the large bandgap of LT‐GaAs limits its operation to gating at wavelengths shorter than 870 nm. Here, it is demonstrated for the first time that nanostructuring the LT‐GaAs into a highly absorbing metasurface enables THz photoconductive detection with a pulsed laser at λ = 1.55 µm. The very weak sub‐bandgap absorption mediated by midgap states in LT‐GaAs is strongly enhanced using the concept of perfect absorption via degenerate critical coupling. Integrated with a THz antenna, the LT‐GaAs metasurface enables high sensitivity THz detection with a high dynamic range of 60 dB and large bandwidth up to 4.5 THz. The LT‐GaAs metasurface has the potential to serve as a universal ultrafast switching element for THz applications, enabling low‐cost, turn‐key THz systems for a variety of real‐world applications.

show abstract

A comprehensive study of ultrafast carrier dynamics of LT-GaAs: Above and below bandgap regions

Cited by 14 publications

References 43 publications

Tuning the Plasmonic Response of AuGe Nanoparticles on GaAs Substrates: Implications for Photodetectors

Tuning the Plasmonic Response of AuGe Nanoparticles on GaAs Substrates: Implications for Photodetectors

1550 nm Compatible Ultrafast Photoconductive Material Based on a GaAs/ErAs/GaAs Heterostructure

Terahertz Detection Using Enhanced Two‐Step Absorption in Photoconductive Metasurfaces Gated at λ = 1.55 µm

Contact Info

Product

Resources

About