Browsing by Subject "Semiconductor-metal Photodetectors"

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    Random sized plasmonic nanoantennas on Silicon for low-cost broad-band-near-infrared photodetection
    (Nature Publishing Group, 2014-11-19) Nazirzadeh, M. A.; Atar, F. B.; turgut, B. B.; Okyay, Ali Kemal
    In this work, we propose Silicon based broad-band near infrared Schottky barrier photodetectors. The devices operate beyond 1200 nm wavelength and exhibit photoresponsivity values as high as 3.5 mA/W with a low dark current density of about 50 pA/mu m(2). We make use of Au nanoislands on Silicon surface formed by rapid thermal annealing of a thin Au layer. Surface plasmons are excited on Au nanoislands and this field localization results in efficient absorption of sub-bandgap photons. Absorbed photons excite the electrons of the metal to higher energy levels (hot electron generation) and the collection of these hot electrons to the semiconductor results in photocurrent (internal photoemission). Simple and scalable fabrication makes these devices suitable for ultra-low-cost NIR detection applications.
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    Structural and electrical characterizations of InxGa1-xAs/InP structures for infrared photodetector applications
    (AIP Publishing LLC, 2014-03-12) Asar, T.; Özçelik, S.; Özbay, Ekmel
    Three InGaAs/InP structures for photodetector applications were grown with different indium compositions by MBE technique. The structural properties of the samples have been obtained by means of high resolution X-ray diffraction and secondary ion mass spectrometry measurements. Three InGaAs/InP metal-semiconductor-metal devices were fabricated at room temperature. The experimental forward and reverse bias current-voltage characteristics of the devices such as ideality factor, barrier height, and saturation current were evaluated considering the structural properties of the grown structures. The carrier recombination lifetime and diffusion length in the devices were also calculated using carrier density and mobility data obtained with Hall effect measurement at room temperature. It was determined that all room temperature fabricated devices improved the Schottky barrier height. Especially, the device fabricated on the lower mismatched structure exhibited barrier height enhancement from 0.2 eV, which is the conventional barrier height to 0.642 eV. In addition, the obtained results show that the room temperature fabricated devices on InGaAs/InP structures can be convenient for infrared photodetector applications. (C) 2014 AIP Publishing LLC.