Analysis of photonic crystal and multi-frequency terahertz microstrip patch antenna

In this paper, two-dimensional photonic crystals working at terahertz (THz) frequency is analyzed, a multi-frequency terahertz microstrip patch antenna on photonic crystal substrate is presented and its electromagnetic wave propagation phenomenon is investigated. The proposed antenna can work at five frequency points' scope at terahertz frequency regions, and the radiation efficiency is as high as similar to 96%. The photonic crystal structure of the substrate is used to enhance the gain, directivity and radiation efficiency of the antenna. (C) 2013 Elsevier B.V. All rights reserve

Ultra-Wideband Multi-Frequency Terahertz Square Microstrip Patch Antenna on Hybrid Photonic Crystal Substrate

In this paper, two-dimensional photonic crystals working at terahertz frequency is investigated, and an ultra-wideband terahertz microstrip patch antenna on hybrid photonic crystal substrate is presented. Microwave Studio software is used to simulate its electromagnetic wave transmission properties. The proposed antenna can work at six frequency points' scope at terahertz frequency regions, and the 10 dB bandwidth is higher than ∼59%. The hybrid photonic crystal structure is able to provided ultra wide stop-band spectrum, in addition to advantages of the traditional photonic crystal structure which can enhance the gain, directivity and radiation efficiency of the antenna

Extraordinary Transmission Based on Deep Perforated Sub-Wavelength Metallic Hole Arrays for Infrared Photodetector

In this paper, a new mode of deep perforated sub-wavelength metallic hole arrays in hexagonal lattice is presented. The transmission spectrum is obtained with Finite-difference time-domain (FDTD) and measured with Fourier infrared spectrometer. In the resonance peak scope, the Electric-field intensity is similar to 80 times larger than that of the incident wave at near field. The resonance of this structure can enhance the near-field intensity and improve the absorption efficiency of photodetector

The effect of Ga-doped nanocrystalline ZnO electrode on deep-ultraviolet enhanced GaN photodetector

Two types of GaN-based ultraviolet (UV) photodetectors were fabricated by using NiAu and Ga-doped ZnO (GZO) as electrode materials, respectively. Dark current-voltage and photoresponse characteristics of the devices were investigated. It is found that in addition to the similar to 365 nm cut-off response of GaN, an enhanced responsivity at around 250 nm is achieved for the GZO/GaN photodetectors. Photo absorption measurements provide proof that the efficient deep UV absorption occurs in the solar blind spectral zone. Transmission electron microscopy observations reveal the existence of nanostructures in the GZO thin film. Such nanostructures could be responsible for the deep UV photoresponse

Bias-voltage dependent ultraviolet photodetectors prepared by GaOx + ZnO mixture phase nanocrystalline thin films

Ultraviolet (UV) photodetectors were prepared by using the GaOx + ZnO mixture phase thin films sputtered on sapphire as the photoresponse layer. The devices show good photoresponse in UV range. More interestingly, the device responsivity in the wavelength less than 280 nm range rapidly increases with increasing the applied voltage and becomes dominant for the bias >= 3.0 V. X-ray diffraction, absorption and cathodoluminescence measurements firmly reveal the mixture phases in the thin films. Electric field dependent detrapping of photo-excited carriers in nanocrystals in the films shall be responsible for the observed bias-voltage dependent deep UV photoresponse of the devices