Browsing by Author "Hajo, Ahid S."

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    Enhanced Responsivity of ZnSe-bazed Metal-Semiconductor-Metal Near-Ultraviolet Photodetector via Impact Ionization [Articol]
    (Willey, 2018) Sirkeli, Vadim; Yilmazoglu, Oktay; Hajo, Ahid S.; Nedeoglo, Natalia; Nedeoglo, Dmitrii; Preu, Sascha; Küppers, Franko; Hartnagel, Hans
    We report on high‐responsivity, fast near‐ultraviolet photodetectors based on bulk ZnSe employing a metal–semiconductor–metal structure with and without interdigital contacts. A very high responsivity of 2.42 and 4.44 A W−1 at 20 V bias voltage and high rejection rate of 7900 and 4810 for the light with a wavelength of 325 nm is obtained for photodetectors without and with interdigital contacts, which indicates an internal gain. The mechanism of internal gain is attributed to the impact ionization of ZnSe atoms under high internal electric field strength of 133 kV cm−1. Also a low dark current of ≈3.4 nA and high detectivity of ≈1.4 × 1011 cm Hz1/2 W−1 at a voltage of 20 V is achieved for the device with interdigital contacts at room temperature.
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    Recent advances in ZnSe-based devices: from UV to terahertz applications [Articol]
    (CEP USM, 2024) Sirkeli, Vadim P.; Nedeoglo, Natalia D; Nedeoglo, Dmitrii D.; Vatavu, Sergiu A.; Yilmazoglu, Oktay; Hajo, Ahid S.; Preu, Sascha; Hartnagel, Hans L.; Küppers, Franko
    Zinc selenide is a II-VI compound material with wide bandgap. Due to its unique properties like direct wide bandgap, high resistance to intense UV and X-Ray radiation, ZnSe is attractive material for fabrication of many photonic and electronic devices. In this paper we report on recent advances on ZnSe-based optoelectronic devices covering spectral region from ultraviolet to terahertz.