properties toward next-generation electronic, optoelectronic, and photovoltaic devices, [1,5-8] such as field-effect-transistors, [9-11] and infrared detectors. [12,13] For instance, high mobility up to 77 000 cm 2 V −1 s −1 have been reported in InSb NWbased field-effect-transistors. [9] The use of InSb NWs to realize IR detectors working from mid-to long wavelength region has been reported. [14,15] Mid-infrared photodetectors based on a metal-semiconductormetal structure have been fabricated using electrochemically synthesized InSb NWs, showing high stability and excellent responsivity (8.4 × 10 4 AW −1). [15] Such enhanced properties have been explained in terms of high surface-to-volume ratio and 1D nanostructure of the photodetectors that significantly reduce the scattering and trapping phenomena, as well as the transit time between the electrodes. Multispectral optical absorptance in the short and mid-IR regions has been demonstrated [12] in top-down etched InSb NWs arrays, obtained by reactive ion etching of thin films produced by molecular beam epitaxy. In particular, it is possible to obtain highly tunable absorptance from 1.61 to 6.86 µm. [12] Furthermore, InSb NWs with diameter below 50 nm reach the quantum capacitance limit, providing significant improvement in device performance. [16] Single crystalline n-type InSb NWs have also been demonstrated as gas sensors at room temperature for NO 2 detection down to one part-per-million. [17] InSb NWs are promising candidates also for developing large area cold cathodes. It has been reported that the electron tunneling barrier is reduced due to high carrier concentration and relevant surface accumulation layer in InSb NWs. [18] This InSb nanowire arrays with different geometrical parameters, diameter and pitch, are fabricated by a top-down etching process on Si(100) substrates. Field emission properties of InSb nanowires are investigated by using a nano-manipulated tip anode inside of a scanning electron microscope. Stable field emission current is reported, with a maximum intensity extracted from a single nanowire of 1 µA, corresponding to a current density as high as 10 4 A cm −2. Stability and robustness of the nanowire is probed by monitoring field emission current for about 3 h. By tuning the cathode-anode distance in the range 500-1300 nm, the field enhancement factor and the turn-on field exhibit non-monotonic dependence, with maximum enhancement β ≈ 78 and minimum turn-on field E ON ≈ 0.033 V nm −1 for a separation d = 900 nm. The reduction of pitch between nanowires and the increase of diameter cause the reduction of the field emission performance, with reduced field enhancement (β < 60) and increased turn-on field (E ON ≈ 0.050 V nm −1). Finally, finite element simulation of the electric field distribution in the system demonstrates that emission is limited to an effective area near the border of the nanowire top surface, with annular shape and maximum width of 10 nm.
InSb nanowire (NW) arrays fabricated by a top-down etching process were investigated for multispectral infrared photodetection. A 2.5 μm thick film of InSb was grown on Si (100) by molecular beam epitaxy using an AlSb buffer layer to alleviate defects associated with lattice mismatch strain, as confirmed by scanning electron microscopy and x-ray diffraction. Using a Ti mask patterned by electron beam lithography, InSb NW arrays with diameters ranging from 300 to 1300 nm (100 nm steps) and pitches ranging from 1000 nm to 3500 (500 nm steps) were reactive ion etched from the thin film. For each 100 nm increase in NW diameter, the peak absorptance wavelength, as measured by Fourier transform infrared spectroscopy, increased by 0.53±0.2 μm. The ability of InSb nanowires to produce highly tunable absorptance from 1.61 to 6.86 μm was demonstrated.
We report on the selective area growth of InAs nanowires (NWs) by the catalyst-free vapor−solid method. Well-ordered InAs NWs were grown on GaAs(111)B and Si(111) substrates patterned with a dielectric mask using hydride vapor phase epitaxy (HVPE). Vertical and high aspect ratio InAs NWs with a hexagonal shape were grown on both GaAs and Si substrates. The impact of the growth conditions on the InAs morphology was investigated. The final shape of the InAs crystal was tuned from a NW to a nanoplatelet by controlling growth conditions such as growth temperature, vapor phase composition, and mask pattern. The influence of the aperture size on the nucleation density and then on the morphology of InAs is discussed. Small openings resulted in the formation of a single nucleus per hole, which was then converted to a NW. For larger apertures, the number of nuclei increased, leading to both three-dimensional crystals and NWs. The effect of growth temperature and the III/V ratio on the kinetics and thermodynamics of InAs growth is also discussed. The growth was first optimized on a GaAs(111)B substrate and then performed on Si, which is more suitable to develop devices. Finally, the absorbance and photoluminescence measurements were carried out on the InAs NW arrays, demonstrating the high potential of HVPE-grown InAs NWs for future multispectral photo-detection devices.
No abstract
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.