Diameter Of Nanowires Research Articles

Plausible Colloidal Methods to Synthesize Semiconductor Nanowires: Deep Study From ZnSe Nanorods

AbstractWhen the diameter of semiconductor nanowires is below the Bohr radius, confined excitons in the radial direction can freely move along the elongated axis direction, highlighting their potential for applications in quantum information and optoelectronic devices. Controlled anisotropic growth and oriented attachment are viable strategies for producing ultra‐long semiconductor nanowires with precisely controlled lengths and diameters. Anisotropic ZnSe nanorods are used as the initial seeds for the controlled anisotropic growth and oriented attachment methods. ZnSe nanorods/nanowires with limiting lengths of tens to hundreds of nanometers are produced. The advantages and limitations of semiconductor nanowires via controlled anisotropic growth and oriented attachment are summarized. The perspective for the promotion of controlled anisotropic growth and oriented attachment is discussed, which allows to promotion of the precise synthesis of semiconductor ultra‐long nanowires to develop the fundamental research and applications of ultra‐long semiconductor nanowires.

Synthesis of Sn-catalyzed Ge nanowires and Ge/Si heterostructures via a gradient method

In this study, we investigate the growth of Ge nanowires (NWs) using a gas supply gradient method during plasma-enhanced chemical vapor deposition (PECVD), focusing on the effects of GeH4 partial pressure and total chamber pressure on NWs morphology. By adjusting either the GeH4 flow rate or the total pressure, we explored a gradient method to manipulate the growth process. Scanning electron microscopy (SEM) images revealed that, even with constant GeH4 partial pressure, variations in total pressure significantly influenced NWs diameter and structure. Furthermore, elemental mapping and compositional analysis demonstrated the presence of a Ge/Si heterostructure with a Sn catalyst at the apex and an amorphous Si layer encapsulating the NW surface.

Dependence of nanowire length, diameter, and concentration on the electrochromic properties of hybrid silver nanowire network/PEDOT:PSS-based devices

Mixing silver nanowires is a relevant tool to increase the overall conductivity of hybrid electrochromic systems. Herein, the addition of silver nanowires with an average diameter of 30 nm, length of 88 um, and concentration of 3.0 mg/ml lowered the sheet resistance of PEDOT:PSS films from 280 Ω/sq to 34 Ω/sq. Further characterized for their electrochromic behavior, mixing silver nanowires with PEDOT:PSS films allowed lowering the turn-on voltage from -1.5 V to -1.1 V and reducing the switching time from 7 to 3.6 seconds. Furthermore, with the addition of silver nanowires into PEDOT:PSS, an expensive ITO transparent and environmentally impactful electrode material is no longer required. Electrochromic devices based on hybrid AgNW/PEDOT:PSS films showed higher colouration efficiency, lower sheet resistance, lower turn on voltage, and faster switching times as compared to electrochromic devices made with PEDOT:PSS films only.

Optical Properties of Gold Nanoparticles Doped P3HT Nanowires Films

Poly (3-hexyl-thiophene-2,5-diyl) (P3HT) material is widely used as the benchmark of p-type semiconductors in organic photovoltaics due to its high conductivity and self-assembly into nanowires. In this study, gold-doped P3HT nanowires were synthesized using o-xylene, and their optical and electronic changes were investigated. P3HT nanowires were kept in the dark for 72 hours to obtain 60 – 80 nm diameter of nanowires. 1 mM of chloroauric acid doping was used as glass-coated P3HT nanowires were dipped repetitively into the chloroauric acid solution. It was found that visible absorbance intensity reduced and the calculated optical bandgap energy of P3HT nanowires thin film decreased as much as 0.08 eV after doping. FTIR and Raman show there are no extreme changes in P3HT conjugated backbones structure after doping meaning that the gold did not completely integrate within nanowires. From this observation, we discussed the feasibility of this coating method to produce metal-doped organic film and the required improvement to suit photonic device applications.

Synthesis and field emission characterization of La-doped SiC nanowires using graphite powder as carbon source

Lanthanum (La)-doped SiC nanowires (NMs) were synthesized via a carbon thermal reduction process using different graphite powders, while milled Si-SiO2 mixed powders were employed as the silicon source. The identification of the products as β-SiC were supported by Select-area electron diffraction (SAED) and X-ray diffraction (XRD) analysis. The field emission results demonstrated that the turn-on field reached a minimum value of approximately 2.3 V/μm when the graphite content ranged from 2.5 g–3 g. The product exhibited higher density at this stage, accompanied by an increase in nanowire diameter and a tendency toward straightness. The energy spectrum analysis revealed a significant increase in the lanthanum content within the nanowires, with the atomic percentage rising from 0.05 to 0.26–0.27. The synergistic effect of morphology and La improved the field emission performance of the product. The findings may offer valuable insights for enhancing the field emission performance of one-dimensional nanomaterials.

Ultra-dense Green InGaN/GaN Nanoscale Pixels with High Luminescence Stability and Uniformity for Near-Eye Displays.

Ultra-dense (>4,000 pixels per inch) and highly stable full-color III-nitride nanoscale pixels are crucial for near-eye display technologies like virtual and augmented-reality glasses. In this context, InGaN-based long wavelength green microscale light-emitting diodes face major bottlenecks, such as low efficiency and inadequate wavelength stability. These challenges are associated with the presence of both nonradiative surface defects and the strain induced quantum-confined Stark effect. Herein, we report nanoscale pixelation of green InGaN/GaN LEDs incorporating strain-engineered ultra-dense nanowire (NW) arrays, corresponding to ∼36,000 pixels per inch. The NW pixel arrays exhibit a stable peak wavelength emission at ∼500 nm for over 3 orders of magnitude of injection current densities (from ∼4 A/cm2 to ∼1 kA/cm2). The observed wavelength stability enhancement (a reduced blue-shift of just ∼4 nm) directly results from the suppressed built-in electric field achieved by strain relaxation of the axial multi quantum wells in the NWs. Finite difference time domain simulations show that emission of the pixel array is significantly increased owing to the enhanced spontaneous emission rate (characterized by a high Purcell factor of ≈2) of the ultra-dense NWs. We have demonstrated top-down NWs, where each NW (diameter ranging down to 200 nm) shows excellent uniformity and light output characteristics in direct contrast to bottom-up grown NW heterostructures. The results of this study establish a viable route for realizing nanoscale pixels with high luminescence stability and wafer-scale uniformity with high (>20%) indium composition InGaN/GaN LED heterostructures, for next-generation near-eye displays.

Double-formant PCF-SPR refractive index sensor with ultra-high double-peak-shift sensitivity and a wide detection range

A dual-resonance-peak photonic crystal fiber–surface plasmon resonance (PCF-SPR) refractive index (RI) sensor is designed for different wavelength ranges. The first resonance peak of the sensor is distributed in the wavelength range of 700–2350 nm, while the second peak is distributed in the range of 2350–5550 nm. In addition to detecting analytes using the full spectrum of constraint losses (CLs), it is also possible to use a single resonance peak to achieve the detection of analytes. By systematically optimizing the nanowire diameter, the diameter of the inner and outer layer air hole, the width of the groove, the polishing depth, and the distance from the outer layer air hole to the fiber core, the optimal structure of the sensor is finally determined. In this study, the sensor was studied by numerical analysis, and the characteristics of the sensor were evaluated by wavelength detection technology. The results show that within the RI range of 1.24–1.37, the sensor has a maximum wavelength sensitivity (WS) of 54700 nm/RIU for detecting the RI of analytes. Within the above refractive index range, the regression coefficient R2 of the dual-peak-resonance wavelength is 0.99993, ensuring the accuracy of the estimated resonance wavelength of the sensor. In addition, the sensor can also use dual-peak-shift sensitivity (DPSS) to detect the refractive index, which is a relatively new sensing technology. The maximum DPSS of the sensor is 95300 nm/RIU. Due to its high sensitivity and unique dual-peak characteristics, this sensor has wide application prospects in medical diagnosis, environmental monitoring, food safety, and other fields.

Shape-controlled growth of beta-gallium oxide nanowires and experimental investigation on the origination of electrons

Diameter-controlled growth of monoclinic gallium oxide nanowires was performed by chemical vapor deposition technique. Prior to growth, a thin layer of Au films was fabricated, SEM images indicated that Au could converge nanoparticles to govern the growth of β-Ga2O3 nanowires. The SEM images revealed both diameter and length of β-Ga2O3 nanowires strongly depended on the growth temperature. Nanowires grown at 1100 °C temperature have the minimum diameters and uniform lengths, compared with those grown at 900 °C and 1000 °C. The reasons are that a combination and a competition of vapor-liquid-solid (VLS) and vapor-solid (VS) mechanism occur in the growth process. High temperature would provide enough energy to make Ga and O atoms grow along one-dimensional axial orientation following the VLS mechanism. However, low temperature confines atoms at the nanowires interface and enhance sidewalls coalescence following the VS mechanism. X-ray diffraction (XRD) patterns and refinement indicated that the grown samples were of high crystallinity and had intrinsic oxygen vacancies. Photoluminescence spectra were examined and then followed by Gaussian fitting. Through analysis, the emission peaks were considered to originate from intrinsic oxygen vacancies and Ga-O vacancy pairs, consisting with the XRD refinement results. β-Ga2O3 nanowires was coated on the interdigitated electrode, the response to the ultraviolet light and oxygen was studied.

Construction of 2D/1D rGO/H2Ti3O7 composite as anode for high performance lithium-ion batteries

Ultrafine one-dimensional (1D) H2Ti3O7 nanowires were prepared by a hydrothermal reaction with high concentration of KOH as base source. Then 2D/1D rGO/H2Ti3O7 architecture was constructed and investigated as the anode material for lithium-ion batteries. Benefiting from the addition of rGO nanosheets and the retention of ultrafine 1D H2Ti3O7 nanowires, the rGO/H2Ti3O7 electrode presented superior electrochemical performance with excellent rate capability, long cycling stability and high capacity in half cells. It delivered high reversible capacities of 274 mAh g−1 at 0.1 A g−1 and 163 mAh g−1 at 1 A g−1, as well as a long-term cycling performance (259.3 mAh g−1 at 0.2 A g−1 after 1000 cycles). The excellent electrochemical performance of the composite can be attributed to the unique architecture with smaller diameter of 1D H2Ti3O7 nanowires and conductive rGO nanosheets to shorten the transmission distance of electrons and Li+ and improve the electrical conductivity in rGO/H2Ti3O7 composite.

Comparative study in magnetic properties of FeCo alloy nanowires and a first-order reversal curve analysis

FeCo alloy nanowires have potential applications in data storage, magnetic sensors and spintronic devices. In this paper, FeCo alloy nanowires with varying diameters were fabricated within an anodic aluminum oxide (AAO) template using electrodeposition method at a constant potential. Characterization of the morphology and structure revealed that the polycrystalline body-center-cubic(bcc) FeCo alloy nanowires were obtained. The influence of diameter of FeCo alloy nanowires on magnetic interaction, domain state and magnetic mechanism was investigated through a first-order reversal curve (FORC) analysis. The findings showed that with an increase in the diameter of FeCo alloy nanowires from 20 nm to 60 nm and 100 nm, the interaction force between the FeCo alloy nanowires increased, the domain state of FeCo alloy nanowires changed from Single Domain (SD) to Multi-Domain (MD), the magnetic reversal mode changed from coherent reversal mode to curling reversal mode.

(Invited) The Influence of Magnetic Fields on the Oxygen Evolution Reaction Catalyzed By Cobalt-Iron Oxide Nanowire Arrays

To mitigate climate change through the establishment of a renewable energy infrastructure, advancements in energy storage technologies are imperative. Electrochemical water splitting via electrolyzers enables the conversion of electrical energy into chemical energy. However, the performance of these devices, particularly that of the oxygen evolution reaction (OER) occurring at the anode, still needs to be improved. Previous studies have demonstrated that magnetic fields can induce convective flow to the electrode through Lorentz and Kelvin force effects, thereby improving the mass transport.[1] In contrast to the Lorentz force, the Kelvin force can be substantially increased by introducing magnetic nanostructures to create high magnetic field gradients in the vicinity of the electrode surface.[2] Given the magnetic properties inherent to many earth-abundant metal-based and nanostructured electrocatalysts promising for the OER, there is potential for intelligently designing electrodes to leverage magnetic field effects in the future. However, a comprehensive understanding of these magnetic field effects is currently lacking. In the scope of this work, we aimed to systematically investigate the influence of magnetic fields on the oxygen evolution reaction. Considering the substantial magnetic field gradients generated by magnetic nanowires, we fabricated arrays of freestanding cobalt-iron oxide nanowires to explore the influence of magnetic fields on the oxygen evolution reaction catalyzed by these nanostructured electrocatalysts. Templated electrodeposition of cobalt-iron alloy into the pores of anodic aluminum oxide membranes enabled a straightforward control over nanowire diameter and length. Subsequent removal of the aluminum oxide template in alkaline solution yielded cobalt-iron oxide nanowires composed to 60% of Fe and 40% of Co standing freely on an electrochemically stable gold substrate. Superimposing a magnetic field during water oxidation on the so-prepared nanowire arrays resulted in an increase in the measured oxidation current (see Figure). To deconvolute the contributions of the Lorentz and Kelvin force, experiments were conducted in two different magnetic field orientations: either parallel or perpendicular to the electrode surface. In the parallel orientation, a linear correlation between the increase in current and the strength of the applied magnetic field was observed. In contrast, when the magnetic field was aligned perpendicular to the electrode surface, a plateau in the current enhancement manifested at higher magnetic field strengths, indicating different dominant effects in the two configurations.[1] K. Ngamchuea, K. Tschulik, R. G. Compton, Magnetic control: Switchable ultrahigh magnetic gradients at Fe3O4 nanoparticles to enhance solution-phase mass transport, Nano Res. 2015, 8, 3293–3306.[2] L. M. Monzon, J. Coey, Magnetic fields in electrochemistry: The Kelvin force. A mini-review, Electrochem. commun. 2014, 42, 42–45. Figure 1

Inverse-designed multi-diameter InAs nanowire array ultra-broadband photodetectors enhanced by localized surface plasmon resonances

Multi-diameter InAs nanowire array ultra-broadband photodetectors are inversely designed and further enhanced by localized surface plasmon resonances. The nanowire diameters are carefully selected by the particle swarm optimization algorithm within the range of 100-800 nm. The multi-diameter nanowire array exhibits high absorption over 80% within a broadband wavelength range of 0.5-3.42 µm, much wider and flatter than that of the single-diameter counterpart, which is attibuted to the superposition of multiple absorption peaks as well as the extension of absorption to longer wavelengths. By introducing indium tin oxide nanoparticles onto the nanowire surface, the lowest absorption is further raised to 87% within a broad wavelength range of 0.55-3.5 µm due to the localized surface plasmon resonances, and the dark current density is substantially reduced from 214 mA/cm2 to 83 mA/cm2 due to the large depletion region. This work may pave the way for the development of ultra-broadband high-responsivity infrared photodetectors.

Patterning optimization for device realization of patterned GaAsSbN nanowire photodetectors

Vertically grown nanowires (NWs) are a research interest in optoelectronics and photovoltaic applications due to their high surface to volume ratio and good light trapping capabilities. This study presents the effects of process and design parameters on self-catalyzed GaAsSbN NWs grown by plasma-assisted molecular beam epitaxy on patterned silicon substrates using electron beam lithography. Vertical alignment of the patterned NWs examined via scanning electron microscopy show the sensitivity of patterned NW growth to the parameters of NW diameter, pitch, dose time, etching techniques and growth plan. Diameters range from 90 nm to 250 nm. Pitch lengths of 200 nm, 400 nm, 600 nm, 800 nm, 1000 nm, and 1200 nm were examined. Dry etching of the oxide layer of the silicon substrate and PMMA coating is performed using reactive ion etching (RIE) for 20 s and 120 s respectively. Comparisons of different HF etch durations performed pre and post PMMA removal are presented. Additionally, the report of an observed surfactant effect in dilute nitride GaAsSbN NWs in comparison to non-nitride GaAsSb is presented. Optimizations to patterning, RIE, and HF etching are presented to obtain higher vertical yield of patterned GaAsSbN NWs, achieving ∼80% of the expected NW µm2. Room temperature and 4 K photoluminescence results show the effect of nitride incorporation for further bandgap tuning, and patterned pitch on the optical characteristics of the NWs which gives insights to the compositional homogeneity for NWs grown at each pitch length.

Diameter-dependent phase selectivity in 1D-confined tungsten phosphides

Topological materials confined in 1D can transform computing technologies, such as 1D topological semimetals for nanoscale interconnects and 1D topological superconductors for fault-tolerant quantum computing. As such, understanding crystallization of 1D-confined topological materials is critical. Here, we demonstrate 1D template-assisted nanowire synthesis where we observe diameter-dependent phase selectivity for tungsten phosphides. A phase bifurcation occurs to produce tungsten monophosphide and tungsten diphosphide at the cross-over nanowire diameter regime of 35–70 nm. Four-dimensional scanning transmission electron microscopy is used to identify the two phases and to map crystallographic orientations of grains at a few nm resolution. The 1D-confined phase selectivity is attributed to the minimization of the total surface energy, which depends on the nanowire diameter and chemical potentials of precursors. Theoretical calculations are carried out to construct the diameter-dependent phase diagram, which agrees with experimental observations. Our findings suggest a crystallization route to stabilize topological materials confined in 1D.

In-situ synthesis of SiC/SiO2 nanowires by catalyst-free thermal evaporation of silicon powder and their photoluminescence properties

Core-shell structured SiC/SiO2 nanowires (SiC/SiO2 NWs) were synthesized by a simple thermal evaporation method without a catalyst. The influence of the growth temperature and holding time on the microstructure and composition of the nanowires were investigated. The results indicate that within the temperature range of 1150 to 1550 °C, the color of SiC/SiO2 nanowires gradually transitions from pure white to off-white with increasing temperature. During this process, the average diameter of SiC/SiO2 increases from ∼74 nm to ∼291 nm, while the surface SiO2 layer thickness decreases from ∼17 nm to ∼5 nm, with nanowires can reach lengths of hundreds of micrometres. Variations in supersaturation of SiO and CO at different temperatures lead to discrepancies in nanowire diameter and SiO2 shell thickness. At 1350 °C, prolonged holding time enhances silicon powder reaction, resulting in increased structural disorder of the obtained SiC/SiO2 nanowires. The nanowire growth follows a vapor-solid (VS) mechanism. Additionally, the study demonstrates that the photoluminescence (PL) characteristics of the nanowires exhibit a blue shift attributable to their nanoscale dimensions, while variations in emission spectra correlate with stacking faults, SiC diameter, and SiO2 thickness. This work may be provide a theoretical basis for preparing SiC/SiO2 nanowires with different diameters and SiO2 shell thicknesses, which is crucial for advancing the development and application of SiC/SiO2 nanoceramics.

Structural and electronic properties of AlGaN nanowires modulated by Al component and sectional size: A first principles study with DFT+U method

AlGaN nanowires have plenty of applications in optoelectronic functional devices. However, the electronic characteristics and stability of AlGaN nanowires are rarely explored, especially for an actual prediction of bandgaps with varying Al components. In this work, we utilize first principles calculation with DFT + U method to study the stability, charge redistribution, band structures, density of states of AlxGa1-xN alloy nanowires with x spanning from 0 to 1. The results indicate that the stability of the nanowire is enhanced with increasing nanowire diameter and Al component. The bond length in the outermost layer, vertical to the specified direction, is stretched as the Al component increases. The bandgap of nanowire is larger than that of bulk phase and the bowing parameter of nanowire is relatively low. According to the analysis of density of states (DOS), the migration of band structures is attributed to N-p states at VBM and Ga-s and Al-p states at CBM. The calculation of Crystal Orbital Hamilton Population (COHP) reveals the variation of bandgap with changing Al component and diameter. According to the analysis of electron density difference and charge transfer, Al atom has a stronger electron negativity and the electron density surrounding Ga is more delocalized compared Al atom. The results obtained in this study is expected to give some guidance for the preparation of optoelectronic devices based on AlGaN nanowires.

Transformation of Bi4Cl2S5 into sub-10 nm Bi2O2CO3 nanowires for electrochemical reduction of CO2

The development of highly efficient catalysts for the selective electrochemical reduction reaction of CO2 (eCO2RR) to high-valued formate remains a challenge in achieving carbon neutrality and renewable energy conversion. In this study, ultrathin Bi4Cl2S5 nanowires, synthesized using different branched-chain thiols as sulfur sources, were reported for the first time as precatalysts for eCO2RR to formate. Systematic material characterization demonstrated that Bi4Cl2S5 can undergo in-situ evolution into Bi2O2CO3 nanowires, serving as the genuine electrocatalyst for eCO2RR. Through the fine-tuning of ligands during the synthesis of Bi4Cl2S5 nanowires, the optimized Bi4Cl2S5-derived Bi2O2CO3 nanowires exhibited a maximum formate Faradaic efficiency (FEformate) of 95.3 % in eCO2RR using a traditional H-cell, surpassing other prepared samples. Furthermore, an FEformate of over 92.9 % was achieved in a wide potential window of 500 mV, and high performance was maintained over 20 h. This outstanding performance is attributed to the high intrinsic activity, accelerated charge transfer, and the large electrochemical active surface area associated with the characteristic sub-10 nm diameter nanowire structure. Moreover, density function theory calculations further revealed that Bi2O2CO3 can reduce the energy barriers for the formation of *OCHO intermediate and bolster formate production. Our work provides a novel synthesis strategy for excellent Bi-based catalysts in electrocatalysis.

Effect of the behavior on direct–indirect electronic transitions of SrZrO3 nanowires grown in the crystallographic directions [100] and [110]: Ab-initio study

In the present work, we studied a set of strontium zirconate nanowires of different diameters oriented in the directions [100] and [110]. The density functional theory calculations were performed using the quantum espresso code, which confidently employs a combination of plane waves. In this study, we utilized a pseudopotential proposed by Perdew, Burke, and Ernzerhof to model the exchange–correlation energy using a generalized gradient approximation. In the study’s first phase, we performed a structural optimization of the nanowires by adjusting the atomic positions and lattice parameters. After calculating the electronic band structure and density of states, we found that the strontium zirconate nanowires in this study are semiconductors. The nanowires in the [100] direction have an indirect transition, while those in the [110] direction have a direct transition. Besides, the bandgap varies with diameter. We also calculated the density of states projected. Based on the results, it can be observed that the p orbital of oxygen is the primary contributor to the density of states in the valence region. On the other hand, in the conduction region, the density of states is mainly affected by the d and s orbitals of zirconium. Due to their exceptional electronic properties, strontium zirconate nanowires are up-and-coming candidates for photocatalysis and solar cell applications.

Zincblende InAsxP1-x/InP Quantum Dot Nanowires for Telecom Wavelength Emission.

InAsxP1-x quantum dots (QDs) in InP nanowires (NWs) have been realized as a platform for emission at telecom wavelengths. These QDs are typically grown in NWs with the wurtzite crystal phase, but in this case, ultrathin diameters are required to achieve defect-free heterostructures, making the structures less robust. In this work, we demonstrate the growth of pure zincblende InAsxP1-x QDs in InP NWs, which enabled an increase in NW diameters to about 45 nm, achieved by employing Au-assisted vapor liquid solid growth in a chemical beam epitaxy system. We studied the growth of InP/InAsxP1-x heterostructures with different compositions to control the straight growth along the ⟨100⟩ direction and to tune the emission wavelength. Interestingly, we found that the growth mechanism for pure InAs QDs is different compared to that for InAsxP1-x alloy QDs. This allowed us to optimize different growth protocols to achieve straight growth of the final QD NWs. We successfully obtained the growth of InAsxP1-x QDs with a composition in the range of x = 0.24-1.00. By means of microphotoluminescence measurements, we demonstrate the tunability of the emission in dependence of the InAsxP1-x QD composition and morphology, remarkably observing an emission at the telecom O-band for a 10 nm thick QD with 80% of As content.

Deep-reactive ion etching of silicon nanowire arrays at cryogenic temperatures

The pursuit of sculpting materials at increasingly smaller and deeper scales remains a persistent subject in the field of micro- and nanofabrication. Anisotropic deep-reactive ion etching of silicon at cryogenic temperatures (cryo-DRIE) was investigated for fabricating arrays of vertically aligned Si nanowires (NWs) of a large range of dimensions from micrometers down to 30 nm in diameter, combined with commonly used wafer-scale lithography techniques based on optical, electron-beam, nanoimprint, and nanosphere/colloidal masking. Large selectivity of ∼100 to 120 and almost 700 was found with resists and chromium hard masks, respectively. This remarkable selectivity enables the successful transfer of patterned geometries while preserving spatial resolution to a significant extent. Depending on the requirements by applications, various shapes, profiles, and aspect ratios were achieved by varying process parameters synchronously or asynchronously. High aspect ratios of up to 100 comparable to the best result by metal-assisted wet-chemical etching and sub-μm trenches by DRIE were obtained with NW diameter of 200 nm, at an etch rate of ∼4 μm/min without being collapsed. At the same time, low surface roughness values were maintained on the NW top, sidewall, and bottom surface of ∼0.3, ∼13, and ∼2 nm, respectively, as well as high pattern fidelity and integrity, which were measured using angle-resolved Fourier microscopy, combined atomic force, and scanning electron microscopy on selected NWs. This work establishes the foundation in the controllable development of Si nanoarchitectures, especially at sub-100 nm structures, for energy-harvesting and storage, damage-free optoelectronics, quantum, photovoltaics, and biomedical devices.