Direct synthesized graphene-like film on SiO₂: Mechanical and optical properties

Exploiting CVD technique for carbon deposition from C₂H₂+H₂+N₂ mixture, a graphene-like film synthesized directly on SiO₂ surface of SiO₂-Si structure was obtained. The graphene-like film was grown under thin Ni layer that is easy exfoliated from graphene-SiO₂-Si structure. Surface of the film was sufficiently smooth and reveals no winkles and holes; it has a good homogeneity and perfect adhesion to SiO₂ layer. Studying the micro-Raman spectra showed a graphene-like structure of the film; using atomic force microscopic technique, the thickness of film was determined (0.6 nm). Using spectroscopic ellipsometry and simple Cauchy model enabled us to estimate optical parameters of this graphene-like film

Electrical and light-emitting properties of silicon dioxide co-implanted by carbon and silicon ions

In this paper we explore the electrophysical and electroluminescence (EL) properties of thermally grown 350 nm thick SiO₂ layers co-implanted with Si⁺ and C⁺ ions. The implanting fluencies were chosen in such a way that the peak concentration of excess Si and C of 5-10 at.% were achieved. Effect of hydrogen plasma treatment on electroluminescent and durability of SiO₂ (Si,C) - Si-system is studied. Combined measurements of charge trapping and EL intensity as a function of the injected charge and current have been carried out with the aim of clarifying the mechanisms of electroluminescence. EL was demonstrated to have defect-related nature. Cross sections of both electron traps and hole traps were determined. EL quenching at a great levels of injected charge is associated with strong negative charge capture, following capture of positive charge leading to electrical breakdown of SiO₂ structures

Electroluminescent properties of Tb-doped carbon-enriched silicon oxide

An electroluminescent device utilizing a heterostructure of amorphous terbium doped carbon-rich SiOx (a - SiOx : C : Tb) on silicon has been developed. The a - SiOx : C : Tb active layer was formed by RF magnetron sputtering of a - SiO₁₋x : Cx : H(:Tb) film followed by high-temperature oxidation. It was shown that, depending on the polarity of the applied voltage, the electroluminescence is either green or white, which can be attributed to different mechanisms of current transport through the oxide film – space charge limited bipolar double injection current for green electroluminescence and trap assisted tunneling or Fowler-Nordheim tunneling for white electroluminescence

Electrical properties of nanoscale heterojunctions formed between GaN and ZnO nanorods

Vertical periodic arrays of ZnO nanorods are prepared by hydrothermal growth on GaN templates patterned by focused ion beam. Electro-physical properties of a single vertically-oriented ZnO nanorod are investigated by measuring the current-voltage characteristics using a nanoprobe in a scanning electron microscope. This technique enables to observe the surface morphology of ZnO nanorods simultaneously with their electrical characterization in vacuum. The vacuum chamber rejects the impact of gas adsorption and light irradiation, which both affect the properties of ZnO nanorods. Moreover, mechanical damage and strain induced during the nanorod transfer are eliminated. Nonlinear current-voltage characteristics under the forward bias are explained by the tunneling-recombination process and by the space charge limited current. The high reverse bias current in the p-n heterojunction is attributed to direct tunneling via a narrow tunnel barrie

Optical and electrical characterization of CuO/ZnO heterojunctions

CuO/ZnO p-n heterojunctions are fabricated on ZnO nanorod arrays by sputtering of metallic Cu thin films and by their subsequent thermal annealing at 400 °C. Structural, morphological, and optical properties of both copper oxide nanocrystalline films and zinc oxide nanorod arrays are discussed with the emphasis on the electrical junction properties investigated by current–voltage and impedance spectroscopy measurements. Electrical characteristics of these junctions are sensitive to gas mixtures with a low hydrogen concentration and show fast response and recovery time. The copper oxide/zinc oxide heterojunctions are shown to be more efficient to hydrogen detection at room temperature in comparison with the resistivity sensors based on zinc or copper oxides

Erratum: Electrical and light-emitting properties of silicon dioxide co-implanted by carbon and silicon ions

In this paper, we explore the electrophysical and electroluminescence (EL) properties of thermally grown 350 nm thick SiO₂ layers co-implanted with Si⁺ and C⁺ ions. The implanting fluencies were chosen in such a way that the peak concentration of excess Si and C of 5-10 at.% were achieved. Effect of hydrogen plasma treatment on electroluminescence and durability of SiO2 (Si,C) - Si-system is studied. Combined measurements of charge trapping and EL intensity as a function of the injected charge and current have been carried out with the aim of clarifying the mechanisms of electroluminescence. EL was demonstrated to have defect-related nature. Cross-sections of both electron traps and hole traps were determined. EL quenching at great levels of injected charge is associated with strong negative charge capture, following capture of positive charge leading to electrical breakdown of SiO₂ structures

Influence of Growth Polarity Switching on the Optical and Electrical Properties of GaN/AlGaN Nanowire LEDs

For the development and application of GaN-based nanowire structures, it is crucial to understand their fundamental properties. In this work, we provide the nano-scale correlation of the morphological, electrical, and optical properties of GaN/AlGaN nanowire light emitting diodes (LEDs), observed using a combination of spatially and spectrally resolved cathodoluminescence spectroscopy and imaging, electron beam-induced current microscopy, the nano-probe technique, and scanning electron microscopy. To complement the results, the photo- and electro-luminescence were also studied. The interpretation of the experimental data was supported by the results of numerical simulations of the electronic band structure. We characterized two types of nanowire LEDs grown in one process, which exhibit top facets of different shapes and, as we proved, have opposite growth polarities. We show that switching the polarity of nanowires (NWs) from the N- to Ga-face has a significant impact on their optical and electrical properties. In particular, cathodoluminescence studies revealed quantum wells emissions at about 3.5 eV, which were much brighter in Ga-polar NWs than in N-polar NWs. Moreover, the electron beam-induced current mapping proved that the p–n junctions were not active in N-polar NWs. Our results clearly indicate that intentional polarity inversion between the n- and p-type parts of NWs is a potential path towards the development of efficient nanoLED NW structures

Influence of Growth Polarity Switching on the Optical and Electrical Properties of GaN/AlGaN Nanowire LEDs

For the development and application of GaN-based nanowire structures, it is crucial to understand their fundamental properties. In this work, we provide the nano-scale correlation of the morphological, electrical, and optical properties of GaN/AlGaN nanowire light emitting diodes (LEDs), observed using a combination of spatially and spectrally resolved cathodoluminescence spectroscopy and imaging, electron beam-induced current microscopy, the nano-probe technique, and scanning electron microscopy. To complement the results, the photo- and electro-luminescence were also studied. The interpretation of the experimental data was supported by the results of numerical simulations of the electronic band structure. We characterized two types of nanowire LEDs grown in one process, which exhibit top facets of different shapes and, as we proved, have opposite growth polarities. We show that switching the polarity of nanowires (NWs) from the N- to Ga-face has a significant impact on their optical and electrical properties. In particular, cathodoluminescence studies revealed quantum wells emissions at about 3.5 eV, which were much brighter in Ga-polar NWs than in N-polar NWs. Moreover, the electron beam-induced current mapping proved that the p–n junctions were not active in N-polar NWs. Our results clearly indicate that intentional polarity inversion between the n- and p-type parts of NWs is a potential path towards the development of efficient nanoLED NW structures

Enhancement of carrier mobility in thin Ge layer by Sn co-doping

We present the development, optimization and fabrication of high carrier mobility materials based on GeOI wafers co-doped with Sn and P. The Ge thin films were fabricated using plasma-enhanced chemical vapour deposition followed by ion implantation and explosive solid phase epitaxy, which is induced by millisecond flash lamp annealing. The influence of the recrystallization mechanism and co-doping of Sn on the carrier distribution and carrier mobility both in n-type and p-type GeOI wafers is discussed in detail. This finding significantly contributes to the state-of-the-art of high carrier mobility-GeOI wafers since the results are comparable with GeOI commercial wafers fabricated by epitaxial layer transfer or SmartCut technology. This is an author-created, un-copyedited version of an article accepted for publication/published in [insert name of journal]. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at http://dx.doi.org/10.1088/0268-1242/31/10/10501