Redesigning Photodetector Electrodes as an Optical Antenna

Nano Letters (Impact Factor: 13.59). 01/2013; 13(2). DOI: 10.1021/nl303535s
Source: PubMed

ABSTRACT At the nanoscale, semiconductor and metallic structures naturally exhibit strong, tunable optical resonances that can be utilized to enhance light-matter interaction and to dramatically increase the performance of chipscale photonic elements. Here, we demonstrate that the metallic leads used to extract current from a Ge nanowire (NW) photodetector can be redesigned to serve as optical antennas capable of concentrating light in the NW. The NW itself can also be made optically resonant and an overall performance optimization involves a careful tuning of both resonances. We show that such a procedure can result in broadband absorption enhancements of up to a factor 1.7 at a target wavelength of 660 nm and an ability to control the detector's polarization-dependent response. The results of this study demonstrate the critical importance of performing a joint optimization of the electrical and optical properties of the metallic and semiconductor building blocks in optoelectronic devices with nanoscale components.

  • Source
    • "Excellent electronic transport properties of silicon nanowires can be exploited for biomolecule detection in the dc and frequency dependent detection systems [1]. Germanium and silicon-based nanowire devices can absorb and transduce light to photocurrent [2] [3] [4]. The addition of optical antennas in the nanowire device enhances photodetection by concentrating radiation into a semiconductor nanowire. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Properties of surface plasmon polaritons can be exploited for the miniaturisation of photonic circuits below the optical wavelength scale. Smaller and more sensitive photodetectors can be made by using sub-wavelength semiconductor elements such as germanium or silicon nanowires in combination with nanometer-scale antennas. The proposed nanowire photodetector enables on-chip optical sensing applications with increased sensitivity and reduced size.
    Applied Physics A 11/2013; DOI:10.1007/s00339-013-8070-z · 1.69 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A plasmonic enhanced Schottky diode is proposed and investigated with metallic periodic slits. A narrow-band response (~40nm) could be tuned in a wide spectrum (800~1800nm) by varying the period of the slits.
    Lasers and Electro-Optics Pacific Rim (CLEO-PR), 2013 Conference on; 01/2013
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Optical antennas have been widely used for sensitive photodetection, efficient light emission, high resolution imaging, and biochemical sensing because of their ability to capture and focus light energy beyond the diffraction limit. However, widespread application of optical antennas has been limited due to lack of appropriate methods for uniform and large area fabrication of antennas as well as difficulty in achieving an efficient design with small mode volume (gap spacing < 10nm). Here, we present a novel optical antenna design, arch-dipole antenna, with optimal radiation efficiency and small mode volume, 5 nm gap spacing, fabricated by CMOS-compatible deep-UV spacer lithography. We demonstrate strong surface-enhanced Raman spectroscopy (SERS) signal with an enhancement factor exceeding 10<sup>8</sup> from the arch-dipole antenna array, which is two orders of magnitude stronger than that from the standard dipole antenna array fabricated by e-beam lithography. Since the antenna gap spacing, the critical dimension of the antenna, can be defined by deep-UV lithography, efficient optical antenna arrays with nanometer-scale gap can be mass-produced using current CMOS technology.
    Optics Express 07/2013; 21(14):16561-9. DOI:10.1364/OE.21.016561 · 3.49 Impact Factor
Show more