Large-area sub-micron gap interdigitated THz emitters fabricated by interference lithography and angle evaporation

Huska, Klaus; Klatt, Gregor; Hetterich, J.; Geyer, Ulf; Dekorsy, Thomas; Bastian, G.; Lemmer, Uli

doi:10.1049/el.2009.1648

Cited by 5 publications

(3 citation statements)

References 10 publications

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“…However, the resolution of the shadow mask technique is over 10 μm so that the patterning of electrodes using a shadow mask is not suitable for fabricating devices for studying charge transport phenomena through the micromaterials in the nanoscale regime. Angle evaporation could be one solution to cover the edge area of the thick material by thin metal deposition . However, it is still difficult to fill up the gap between the substrate and the materials by angle evaporation in the case of micromaterials which have circular or hexagonal cross sections.…”

Section: Introductionmentioning

confidence: 99%

Integrating ZnO Microwires with Nanoscale Electrodes Using a Suspended PMMA Ribbon for Studying Reliable Electrical and Electromechanical Properties

Kim

Huang

Yoon

et al. 2014

Advanced Energy Materials

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A simple method for making electrical connections to ZnO microwires is reported. By using a suspended poly(methyl methacrylate) (PMMA) ribbon, it is shown that it is possible to electrically contact 1-2 µm diameter ZnO microwires with metal electrodes that are only 90 nm thick. The contact resistances of ZnO microwire-based electronic devices fabricated by this method are lower than those of devices fabricated by standard electronbeam lithography and evaporation processes. As one of the possible device applications from this fabrication method, suspended ZnO microwire-based electromechanical devices are produced and their piezoelectric properties are investigated. Piezoelectric-induced current is detected when the suspended microwires are induced to vibrate at their resonant frequency. This fabrication method can be readily and generally applied to prepare nanoscale electrodes on micrometer-sized materials and provides a convenient means for studying their electrical and electromechanical phenomena in a reliable manner.as well as electromechanical properties of microstructures in a reliable and a controllable manner.

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Section: Introductionmentioning

confidence: 99%

Integrating ZnO Microwires with Nanoscale Electrodes Using a Suspended PMMA Ribbon for Studying Reliable Electrical and Electromechanical Properties

Kim

Huang

Yoon

et al. 2014

Advanced Energy Materials

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“…Interference lithography and angle metal evaporation has been successfully employed to fabricate microstructured scalable emitters with submicron feature sizes [67]. A much simpler technique is preparing an interdigitated electrode pattern similar to the one illustrated in Fig.…”

Section: Fabrication Techniques For Scalable Microstructured Antennasmentioning

confidence: 99%

Scalable Microstructured Photoconductive Terahertz Emitters

Winnerl

2011

J Infrared Milli Terahz Waves

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The development of scalable emitters for pulsed broadband terahertz (THz) radiation is reviewed. Their large active area in the 1 -100 mm 2 range allows for using the full power of state-of-the-art femtosecond lasers for excitation of charge carriers. Large fields for acceleration of the photogenerated carriers are achieved at moderate voltages by interdigitated electrodes. This results in efficient emission of single-cycle THz waves. THz field amplitudes in the range of 300 V/cm and 17 kV/cm are reached for excitation with 10 nJ pulses from Ti:sapphire oscillators and for excitation with 5 μJ pulses from amplified lasers, respectively. The corresponding efficiencies for conversion of near-infrared to THz radiation are 2.5×10 -4 (oscillator excitation) and 2×10 -3 (amplifier excitation). In this article the principle of operation of scalable emitters is explained and different technical realizations are described. We demonstrate that the scalable concept provides freedom for designing optimized antenna patterns for different polarization modes. In particular emitters for linearly, radially and azimuthally polarized radiation are discussed. The success story of photoconductive THz emitters is closely linked to the development of mode-locked Ti: sapphire lasers. GaAs is an ideal photoconductive material for THz emitters excited with Ti: sapphire lasers, which are widely used in research laboratories. For many applications, especially in industrial environments, however, fiber-based lasers are strongly preferred due to their lower cost, compactness and extremely stable operation. Designing photoconductive emitters on InGaAs materials, which have a low enough energy gap for excitation with fiber lasers, is challenging due to the electrical properties of the materials. We discuss why the challenges are even larger for microstructured THz emitters as compared to conventional photoconductive antennas and present first results of emitters suitable for excitation with ytterbium-based fiber lasers. Furthermore an alternative concept, namely the lateral photo-Dember emitter, is presented. Due to the strong THz output scalable emitters are well suited for THz systems with fast data acquisition. Here the application of scalable emitters in THz spectrometers without mechanical delay stages, providing THz spectra with 1 GHz spectral resolution and a signal-to-noise ratio of 37 dB within 1 s, is

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“…A PC antenna is typically patterned on a high-resistivity silicon lens substrate and used in a terahertz time-domain spectroscopy (THz-TDS) system. The performance of a PC antenna depends mainly on the substrate material, geometry of the active area, geometry of the antenna, and the excitation laser pulse [3][4][5][6][7][8]. Consequently, the overall output of a THz-TDS using a PC antenna can be considered as a spectral convolution of the responses of (i) antenna, (ii) lens substrate, and (iii) photoconductive material to the optical sources.…”

Section: Introductionmentioning

confidence: 99%

Comparative study of stripline dipole antenna on semiinfinite and lens substrates at terahertz frequency

Nguyen

2014

The 8th European Conference on Antennas and Propagation (EuCAP 2014)

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The input impedance and radiation characteristics of a stripline dipole antenna on different substrate schemes are presented. Two radiation environments, a semi-infinite galliumarsenide substrate (hereafter called a "semi-infinite substrate") and a thin gallium-arsenide substrate backed by a silicon lens (hereafter a "lens substrate"), were examined, and the antenna performances were analyzed in a broad frequency range up to 5.0 THz. The semi-infinite substrate approach is useful in the initial investigation of the antenna characteristic itself while saving a significant amount of computational time. The study provides good guidelines for the design of a terahertz photoconductive antenna in that the antenna effect and the lens substrate effect can be individually characterized and optimized for the best possible performance.Index Terms-Terahertz antenna, stripline dipole antenna, semi-infinite substrate, extended hemispherical lens, highpermittivity material.I.

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Large-area sub-micron gap interdigitated THz emitters fabricated by interference lithography and angle evaporation

Cited by 5 publications

References 10 publications

Integrating ZnO Microwires with Nanoscale Electrodes Using a Suspended PMMA Ribbon for Studying Reliable Electrical and Electromechanical Properties

Integrating ZnO Microwires with Nanoscale Electrodes Using a Suspended PMMA Ribbon for Studying Reliable Electrical and Electromechanical Properties

Scalable Microstructured Photoconductive Terahertz Emitters

Comparative study of stripline dipole antenna on semiinfinite and lens substrates at terahertz frequency

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