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Journal of Physical Studies 23(4), Article 4801 [6 pages] (2019)
DOI: https://doi.org/10.30970/jps.23.4801 GRAPHITE/n-SiC UV DETECTORS FABRICATION BY ELECTRON BEAM EVAPORATIONM. M. Solovan, H. P. Parkhomenko, P. D. Marianchuk
Yuriy Fedkovych Chernivtsi National University, |
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Schottky graphite/$n$-SiC diodes were fabricated by deposition of graphite onto an $n$-SiC substrate of $5\times 5\times 0.3$ mm in size, by electron beam evaporation in a universal vacuum system Leybold-Heraeus L560 from compressed pellets of graphite powder at a substrate temperature of $ 650^{\circ}$\,C. The current-voltage (at different temperatures) and capacitance-voltage characteristics were measured. The resistance values of the series and shunt Schottky diodes graphite/$n$-SiC are determined from the voltage dependence of its differential resistance. The dominant mechanisms of the current transfer through a heterojunction in forward and reverse biases are determined. It has been established that the electric current through the investigated heterostructure under forward bias ($0\,{\rm V} < V < 0.5\,{\rm V}$) is formed by overbarrier emission; under a higher forward bias ($0.5\,{\rm V} < V < 0.8\,{\rm V}$), the dominant current transport mechanism is emission-recombinant through the space-charge region. The main current transport mechanism under reverse bias is tunneling through the space-charge region. From the slope of the temperature dependence of the parameter $ a_ {0} $ in the coordinates $ \ \ln a_ {0} = f (10 ^{3} / T) $, the depth of the energy level $ (E_{D} = 0.09 $ eV), which is undergoing tunneling. In the Mott-Schottky coordinates, the dependences of the measured capacitance are plotted, which indicates a uniform distribution of uncompensated donors in the base material. A weak dependence of the slope of the rectilinear sections on the frequency was revealed, which is due to the influence of electrically active surface states at the interface of two semiconductors with different characteristic recharging times. The sensitivity $ (R) $ and detectiveness $ (D^{*}) $ are determined. It is established that the studied Schottky\linebreak graphite/$n$-SiC diodes can be successfully used as ultraviolet radiation detectors in the photodiode mode of operation.
PACS number(s): 81.05.uf, 85.60.Gz