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Surface-related 2D conductivity of nanocrystalline diamond in-plane nanowires
Rezek, Bohuslav ; Babchenko, Oleg ; Vetushka, Aliaksi ; Verveniotis, Elisseos ; Ledinský, Martin ; Fejfar, Antonín ; Kromka, Alexander
Diamond is an attractive material for nanoelectronics, biological interfaces and electrical transducers. Small device dimensions are highly demanded for higher sensitivity, parallelism, remote sensing and reduced costs. Recently we have demonstrated that directly grown nanocrystalline diamond micro-channels (down to 5 um widths) are feasible and fully operational as field-effect transistors using H-terminated surface conductivity.
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Review of nanocrystalline diamond film deposition on silicon and glass substrates down to 400 °C
Potocký, Štěpán ; Babchenko, Oleg ; Ižák, Tibor ; Varga, Marián ; Kromka, Alexander ; Rezek, Bohuslav ; Michalka, M.
We present an overview of a nanocrystalline diamond (NCD) films deposition on silicon and glass substrates by microwave plasma CVD in hydrogen-based gas mixture. The temperature plays a crucial parameter as the diamond growth process is temperature controlled. Use of temperature sensitive substrates demanded reducing substrate temperature. Natural decrease of deposition rate resulted in search of new or nonstandard process parameters which could at least minimize or compensate it. Addition of oxygen containing gasses was found to improve film quality, and increasing deposition speed. Moreover improvement in pre-treatment of foreign substrates allowed deposition of fully closed films in less then 100 nm. Low thickness of NCD always favorable due to lattice mismatch between substrate material and NCD film. Successful adoption of NCD film deposition on silicon and glass allowed us to study surface chemical modification for protein attachment and DNA immobilization.
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Photothermal and photocurrent spectroscopy of wide band gap nanocrystalline semiconductors
Remeš, Zdeněk ; Babchenko, Oleg ; Neykova, Neda ; Varga, Marián
Optical spectroscopy belongs to the most important methods applied to characterize thin films. Photothermal deflection spectroscopy (PDS) as well as the dual beam photocurrent (DBP) spectroscopy in near ultraviolet (200-400 nm), visible (400-700 nm) and near infrared regions (700-2000 nm) are particularly useful for study of the wide band gap semiconductors deposited as thin layers on glass substrates. In our laboratory we focus on optically transparent thin films such as nanocrystalline diamond (NCD) or ZnO nanostructures with size too small to be visualized in optical microscope and the optical absorption edge in the ultraviolet region. In this contribution we summarize how to evaluate the optical absorption edge and the defects in the band gap of these wide band gap nanocrystalline semiconductors.
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Pulsed linear antenna microwave plasma – a step ahead in large area material depositions and surface functionalization
Kromka, Alexander ; Babchenko, Oleg ; Ižák, Tibor ; Potocký, Štěpán ; Davydova, Marina ; Neykova, Neda ; Kozak, Halyna ; Remeš, Zdeněk ; Hruška, Karel ; Rezek, Bohuslav
A technological progress in the large area growth of diamond films and carbon nanotubes by the modified linear antenna MW system is presented. We show a correlation between process parameters and nano- or poly-crystalline film character. A challenging part, diamond coated mirrors or ATR prisms, are shown as multifunctional optical elements suitable for detection of absorbed molecules. Additional positive feature of the presented plasma system is low temperature hydrogen functionalization of diamond films. Finally, we present that combination of pulsed MW plasma with radiofrequency substrate biasing results in growth of oriented CNTs over large area.
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