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URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11797

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Data inicial: 2010Data final: 2019Assunto: search.filters.subject.DLTS

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    Investigation of the effects of gamma radiation on the electrical properties of dilute GaAs1−xNx layers grown by Molecular Beam Epitaxy
    (Current Applied Physics, 2015-10) Araujo, Clodoaldo Irineu Levartoski de; Al-Saqri, Noor Alhuda M.; Felix, Jorlandio Francisco; Aziz, Mohsin; Albalawi, Hind Mohammed A.; Jameel, Dler; Al Mashary, Faisal; Alghamdi, Haifaa; Taylor, David A.; Henini, Mohamed
    This work reports the effect of gamma (γ-) irradiation on dilute GaAsN with nitrogen concentrations ranging from 0.2 to 1.2% with post-irradiation stability using Current–Voltage (I–V) and Deep Level Transient Spectroscopy (DLTS) measurements in the temperature range from 10 K to 450 K. The I–V results indicate that the irradiation effect was more pronounced in the samples with nitrogen concentration of 0.4%. Additionally, the irradiated samples showed an ideality factor higher than the as-grown samples. On the other hand, for temperatures above 265 K the barrier height of the irradiated samples with 0.8% nitrogen is higher than the as-grown samples. The DLTS measurements revealed that after irradiation the number of traps either decreased remained constant, or new traps are created depending on the concentration of nitrogen. For samples with N = 0.2% – 0.4% the number of traps after irradiation decreased, whereas for samples with N = 0.8% − 1.2 % the number of traps remained the same. However, the properties of some traps such as capture cross-sections and density increased by about 2 orders of magnitude. The origin of the defects present before and after irradiation are discussed and correlated.
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    Rapid thermal annealing: An efficient method to improve the electrical properties of tellurium compensated Interfacial Misfit GaSb/GaAs heterostructures
    (Superlattices and Microstructures, 2015-12) Aziz, Mohsin; Felix, Jorlandio F.; Jameel, Dler; Al Saqri, Noor; Al Mashary, Faisal S.; Alghamdi, Haifaa M.; Albalawi, Hind M.A.; Taylor, David; Henini, Mohamed
    The effect of thermal annealing on Te compensated Interfacial Misfit GaSb/GaAs heterostructures is investigated by using two different thermal annealing procedures, namely rapid thermal annealing and furnace annealing. The electrical properties of the devices are studied by using Current–Voltage, Capacitance–Voltage and Deep Level Transient Spectroscopy techniques. It is observed that rapid thermal annealing treatment is superior in terms of improvement of the electrical characteristics compared to furnace annealing treatment. The lowest leakage current and defect concentration are obtained when rapid thermal annealing is employed.
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    High-performance organic/inorganic hybrid heterojunction based on Gallium Arsenide (GaAs) substrates and a conjugated polymer
    (Applied Surface Science, 2015-12-01) Jameel, D.A.; Felix, J.F.; Aziz, M.; Al Saqri, N.; Taylor, D.; Azevedo, W.M. de; Silva Jr., E.F. da; Albalawi, H.; Alghamdi, H.; Al Mashary, F.; Henini, M.
    In this paper, we present an extensive study of the electrical properties of organic-inorganic hybrid heterojunctions. Polyaniline (PANI) thin films were deposited by a very simple technique on (1 0 0) and (3 1 1)B n-type Gallium Arsenide (GaAs) substrates to fabricate hybrid devices with excellent electrical properties. The hybrid devices were electrically characterized using current–voltage (I–V), capacitance–voltage (C–V) and deep level transient spectroscopy (DLTS) measurements in the temperature range 20–440 K. The analysis of I–V characteristics based on the thermionic emission mechanism has shown a decrease of the barrier height and an increase of the ideality factor at lower temperatures for both hybrid devices. The interface states were analyzed by series resistance obtained using the C–G–V methods. The interface state density (Dit) of PANI/(1 0 0) GaAs devices is approximately one order of magnitude higher than that of PANI/(3 1 1)B GaAs devices. This behaviour is attributed to the effect of crystallographic orientation of the substrates, and was confirmed by DLTS results as well. Additionally, the devices show excellent air stability, with rectification ratio values almost unaltered after two years of storage under ambient conditions, making the polyaniline an interesting conductor polymer for future devices applications.