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In this letter, we report on achieving significantly high (~ 6\times ) sheet charge density (ns) in MgZnO/CdZnO heterostructure, as compared with that in MgZnO/ZnO, at lower Mg ( \le 0.15 ) compositions in barrier MgZnO layer, with both heterostructures grown by dual ion beam sputtering technique. Buffer CdZnO and barrier MgZnO layers are probed separately to investigate carrier density in defect prone sputtered layers. Capacitance-voltage measurement and temperature-dependent Hall measurement confirm the presence of quantum confined carrier density at barrier-buffer interface, suggesting that the enhancement in carrier densities in the heterostructure over individual layers is probably due to the formation of 2-D electron gas (2-DEG). [ABSTRACT FROM PUBLISHER]

We report the switchable photovoltaic effects in graphene/BiFeO3/Pt heterostructures. Pure phase polycrystalline BiFeO3 films were deposited on Pt/TiO2/SiO2/Si substrates by pulse laser deposition. A bilayer graphene was transferred onto the BiFeO3 film which serves as transparent conducting electrodes. The heterostructures showed switchable photovoltaic effect depending on ferroelectric polarization directions indicating depolarization field induced separation of photogenerated carriers. The open circuit voltage (VOC) and short circuit current density (JSC) were measured to be ~ 110 mV, ~92 μA/cm² in positive polarity and similar values were obtained when the polarity was reversed. The JSC and VOC also showed rapid response (< 100 ms) as a function of light exposure time. [ABSTRACT FROM AUTHOR]

Highlights: [•] High quality thin film of multiferroic BiFeO3 on SrRuO3 is grown by RF Sputtering. [•] The Pt/BFO/SRO structure showed diode like behavior through I–V measurement. [•] Appreciable VOC and JSC were observed with illumination of white light. [•] The photoresponse at zero bias of BFO film showed rapid increase in photocurrent. [•] Application of BFO film for photosensitive capacitor is demonstrated. [ABSTRACT FROM AUTHOR]

Abstract: A novel multilevel resistive switching was observed in trilayer stacked geometry composed of graphene nano flakes sandwiched between polyvinylidene fluoride layers fabricated by spin coating method, which are expected to fulfill the need of high density data storage memories. External parameters such as current compliance and induced voltage pulse imposed on the devices provided an aid to tune the inherent resistance states. As fabricated devices exhibited multi level switching with stable resistance ratios between different resistance states having excellent data retention and endurance. Space charge limited conduction and Fowler–Nordheim (F–N) tunneling were found to be responsible for the switching mechanism. Graphene enriched with trapping sites provides the adequate environment for F–N tunneling process to occur, resulting in multi-bit resistance states. [Copyright &y& Elsevier]

Abstract: We report valence and conduction band offset measurements in a pulsed laser deposited Ni0.07Zn0.93O/ZnO heterostructure using X-ray photoelectron spectroscopy, valence band spectroscopy and ultraviolet visible spectroscopy. Neglecting the strain effect, the valence band offset was estimated to be 0.32 eV and the conduction band offset comes out to be −0.23 eV. Ratio between conduction band and valence band offset is 0.72. Core level shifting due to Ni doping has also been explained. Magnetotransport study of Ni0.07Zn0.93O film reveals that the charge carriers might be spin polarized at the interface of the heterojunction. [Copyright &y& Elsevier]