Study of patterned GaAsSbN nanowires using sigmoidal model

Johnson, Sean; Pokharel, Rabin; Lowe, Michael A.; Kuchoor, Hirandeep; Nalamati, Surya; Davis, Klinton; Rathnayake, Hemali; Iyer, Shanthi

doi:10.1038/s41598-021-83973-9

Cited by 3 publications

(2 citation statements)

References 41 publications

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“…Dilute N incorporation in III-V semiconductor thin films has been the subject of extensive study [14][15][16][17][18][19][20], though such studies in NWs have been comparatively limited [21][22][23][24][25][26], and to the best of our knowledge, no ultrafast optical or terahertz (THz) studies have been done on dilute nitride NWs. One of the deleterious effects of N incorporation in the host material is the simultaneous incorporation of N-induced defects [18,27].…”

Section: Introductionmentioning

confidence: 99%

“…Our previous studies [28][29][30][31][32] indicate that the defects in GaAsSb and GaAsSbN (N-incorporated GaAsSb) can be effectively compensated by doping the NWs with Te, which provides better control over the photoconductivity and carrier mobility. Significant improvement in NW quality, as assessed by photoluminescence spectroscopy, Raman spectroscopy, and performance of photodetector devices [7,25,26,33,34], was demonstrated. However, these steadystate optical and electrical measurements provide little information on non-equilibrium charge carrier dynamics in NWs, crucial to device performance.…”

Section: Introductionmentioning

confidence: 99%

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Revealing charge carrier dynamics and transport in Te-doped GaAsSb and GaAsSbN nanowires by correlating ultrafast terahertz spectroscopy and optoelectronic characterization

Yuan¹,

Pokharel²,

Devkota³

et al. 2022

Nanotechnology

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Recent advances in the growth of III-V semiconductor nanowires (NWs) hold great promise for nanoscale optoelectronic device applications. Recently, it was found that a small amount of nitrogen (N) incorporation in III-V semiconductor NWs can effectively red-shift their wavelength of operation and tailor their electronic properties for specific applications. However, understanding the impact of N incorporation on non-equilibrium charge carrier dynamics and transport in semiconducting NWs is critical in achieving efficient semiconducting NW devices. In this work, ultrafast optical pump-terahertz probe spectroscopy has been used to study non-equilibrium carrier dynamics and transport in Te-doped GaAsSb and dilute nitride GaAsSbN NWs, with the goal of correlating these results with electrical characterization of their equilibrium photo-response under bias and low-frequency noise characteristics. Nitrogen incorporation in GaAsSb NWs led to a significant increase in the carrier scattering rate, resulting in a severe reduction in carrier mobility. Carrier recombination lifetimes of 33 ± 1 picoseconds (ps) and 147 ± 3 ps in GaAsSbN and GaAsSb NWs, respectively, were measured. The reduction in the carrier lifetime and photoinduced optical conductivities are due to the presence of N-induced defects, leading to deterioration in the electrical and optical characteristics of dilute nitride NWs relative to the non-nitride NWs. Finally, we observed a very fast rise time of ~ 2 ps for both NW materials, directly impacting their potential use as high-speed photodetectors.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Revealing charge carrier dynamics and transport in Te-doped GaAsSb and GaAsSbN nanowires by correlating ultrafast terahertz spectroscopy and optoelectronic characterization

Yuan¹,

Pokharel²,

Devkota³

et al. 2022

Nanotechnology

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Study of n–i–p Axial/Core–Shell Hybrid GaAsSb Dense Nanowire-Based Near-Infrared Photodetectors on Graphene

Kuchoor,

Deshmukh,

Baruah

et al. 2024

ACS Appl. Nano Mater.

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The van der Waals epitaxy integration of III−V compound nanowires (NWs) with graphene substrates is vital for the development of flexible, high-performance, and cost-effective optoelectronic devices. This article details the growth of highdensity n−i−p core−shell (C−S) GaAs 1−x Sb x NWs on surfacefunctionalized monolayer graphene substrates using Ga-assisted molecular beam epitaxy. The impact of Te surfactant on the catalyst droplet, alongside oxygen plasma duration and key growth parameters, namely the lower substrate temperature pausing duration and V/III ratio, is studied, yielding a vertical core GaAs 1−x Sb x NW density of ∼60 μm −2 . Utilizing the optimal parameters, traditional (TCS) and hybrid (HCS) n−i−p C−S architectures are designed, comprising unique axial n-core multiheterostructures with an Sb gradient for bandgap engineering and a high Sb composition near the graphene surface, which is difficult to achieve on Si substrates. The hybrid structure includes an additional intrinsic GaAs 1−x Sb x axial segment over the top of the n-core to enhance absorption and minimize interface effects. High-resolution transmission electron microscopy images and corresponding selective area electron diffraction patterns of these NWs confirm their zinc blend structure. The absence of twins and stacking faults in HCS-configured NWs further attests to their high structural quality. The electrical performance of the ensemble NW devices with the HCS design outperforms TCS, exhibiting a higher responsivity (∼2100 A/W) and detectivity (2.7 × 10 14 Jones), as well as a spectral response extending up to 1.5 μm on graphene. Temperature-dependent C−V and low-frequency noise measurements reveal the HCS photodetector's good thermal stability, with consistent low capacitance, a low cutoff frequency of ∼6 Hz, and minimal shunt resistance variation with temperature. These results showcase that bandgap engineering of GaAsSb in a 1D configuration, coupled with the versatility of architectures offered by 1D geometry and inherent van der Waals forces in graphene, can be successfully exploited to fabricate high-performance photodetectors, advancing their use in the next era of flexible electronic devices.

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Heterostructure axial GaAsSb ensemble near-infrared p–i–n based axial configured nanowire photodetectors

et al. 2023

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In this work, we present a systematic design of growth experiments and subsequent characterization of self-catalyzed molecular beam epitaxially grown GaAsSb heterostructure axial p-i-n nanowires (NWs) on p-Si <111> for the ensemble photodetector (PD) application in the near-infrared (NIR) region. Diverse growth methods have been explored to gain a better insight into mitigating several growth challenges by systematically studying their impact on the NW electrical and optical properties to realize a high-quality p-i-n heterostructure. The successful growth approaches are Te-dopant compensation to suppress the p-type nature of intrinsic GaAsSb segment, growth interruption for strain relaxation at the interface, decreased substrate temperature to enhance supersaturation and minimize the reservoir effect, higher bandgap compositions of the n-segment of the heterostructure relative to the intrinsic region for boosting the absorption, and the high-temperature ultra-high vacuum in-situ annealing to reduce the parasitic radial overgrowth. The efficacy of these methods is supported by enhanced photoluminescence (PL) emission, suppressed dark current in the heterostructure p-i-n NWs accompanied by increased rectification ratio, photosensitivity, and a reduced low-frequency noise level. The PD fabricated utilizing the optimized GaAsSb axial p-i-n NWs exhibited the longer wavelength cutoff at ~ 1.1 µm with a significantly higher responsivity of ~ 120 A/W (@-3 V bias) and a detectivity of 1.1 ×10^13 Jones operating at room temperature. Frequency and the bias independent capacitance in the pico-Farad (pF) range and substantially lower noise level at the reverse biased condition, show the prospects of p-i-n GaAsSb NWs PD for high-speed optoelectronic applications.

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Study of patterned GaAsSbN nanowires using sigmoidal model

Cited by 3 publications

References 41 publications

Revealing charge carrier dynamics and transport in Te-doped GaAsSb and GaAsSbN nanowires by correlating ultrafast terahertz spectroscopy and optoelectronic characterization

Revealing charge carrier dynamics and transport in Te-doped GaAsSb and GaAsSbN nanowires by correlating ultrafast terahertz spectroscopy and optoelectronic characterization

Study of n–i–p Axial/Core–Shell Hybrid GaAsSb Dense Nanowire-Based Near-Infrared Photodetectors on Graphene

Heterostructure axial GaAsSb ensemble near-infrared p–i–n based axial configured nanowire photodetectors

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