Copper oxide (CuO) thin films were prepared by direct oxidation of modified activated reactive evaporated copper nitride (Cu3N) thin films in air ambience. When annealed in air at higher temperatures, Cu3N films undergo complete decomposition and the residual Cu gets easily bonded with the atmospheric oxygen to form CuO. Annealing provides required activation energy for the formation of CuO. The formation of fairly crystallized CuO was confirmed by X-ray diffraction and Raman spectroscopy studies. However, the crystallite size of CuO films is smaller than their corresponding Cu3N phase. The surface morphology of the CuO films obtained through this method shows grains of non-uniform size distribution. Furthermore, Raman spectra on the as-grown Cu3N films were taken by varying the laser power. At higher laser power, microscopic CuO dots are formed due to laser-induced oxidation. It is proposed that p-type CuO can be easily grown over suitably prepared n-type Cu3N by local heating or laser irradiation in air. © 2014, Springer-Verlag Berlin Heidelberg.

Mahaveer Kumar Jain

Department Of Physics

Guruprasad Sahoo

Activation energy

Crystallite size

Film preparation

Metallic films

oxidation

Oxide films

Thin films

X ray diffraction

As-grown

ATMOSPHERIC OXYGEN

COPPER NITRIDE

DIRECT OXIDATION

Laser power

LASER-INDUCED OXIDATION

LOCAL HEATING

MODIFIED ACTIVATED REACTIVE EVAPORATION

Copper

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Applied Physics A: Materials Science and Processing

Using ab initio density functional calculations, we have investigated the stability and electronic structure of pure and oxygen doped semiconducting Cu3N. The oxygen can be accommodated in the system without structural instability as the formation energy either decreases when oxygen substitutes nitrogen, or remains nearly same when oxygen occupies the interstitial position. The interstitial oxygen (OI) prefers to stabilize in the unusual charge neutral state and acts as an acceptor to make the system a p-type degenerate semiconductor. In this case the hole pockets are formed by the partially occupiedOI-p states. Onthe other hand, oxygen substituting nitrogen (OS) stabilizes in its usual2 charge state and acts as a donor to make the system an n-type degenerate semiconductor. The electron pockets are formed by the conducting Cu-p states. In the case of mixed doping, holes are gradually compensated by the donor electrons and an intrinsic gap is obtained for Cu3N1-2xO xO x S 2 I stoichiometry.Our calculations predict the nature of doping aswell as optical band gap (Eg ) opt variation in experimentally synthesized copper oxynitride. While interstitial doping contracts the lattice and increases the Eg , opt substitutional doping increases both lattice size and E . g opt Mixed doping reduces Eg . opt Additionally we show that a rare intra-atomic d-p optical absorption can be realized in the pristine Cu3Nas the Fermi level lies in the gap between the Cu-d dominated antibonding valence state and Cu-p conducting state. © 2016 IOP Publishing Ltd.

Materials Research Express

Tailoring p-and n-type semiconductor through site selective oxygen doping in Cu3N: Density functional studies

Highly crystalline copper nitride (Cu3N) thin films have been deposited on glass substrates at room temperature by a novel and commercially viable growth technique, known as modified activated reactive evaporation (MARE). The effects of change in radio frequency (RF) power and deposition pressure on the structural and optical properties of the films have been investigated. RF power plays a significant role for the preferential growth of these films along a particular plane whereas the deposition pressure has comparatively lesser impact on the same. However, the lattice parameter, film thickness and optical band gap are found to be strongly dependent on the deposition pressure. The MARE grown Cu3N films undergo complete decomposition into metallic Cu upon vacuum annealing at 400 °C which makes them promising candidates to be used in write once optical recording media. © 2014 Elsevier B.V. All rights reserved.

Materials Science and Engineering B: Solid-State Materials for Advanced Technology

Room temperature growth of high crystalline quality Cu3N thin films by modified activated reactive evaporation

Controlled synthesis of CuO nanoparticles with various morphologies were achieved by a wet chemical method by the reduction of copper acetate with NaOH. Influence of surfactant, alkaline concentration and solvent medium on the morphology of nanoparticles was investigated. Our studies reveal that these parameters alter the aggregation-growth processes and hence the morphology. Sodium dodecyl sulphate (SDS) as a structure-guiding agent has a strong impact on the morphology of nanostructure. By adjusting the rate of hydrolysis, two dimensional netted structures consisting of bundles of nanorods were obtained, formed by oriented attachment mechanism. Moreover, well defined and dispersed CuO nanoparticles were produced by manipulating the solvent medium. Optical properties were studied using UV-Vis absorption and Raman spectroscopy. Morphology and size of nanoparticles have a profound effect on the nature of multi-phonon band observed in the Raman spectra of CuO nanostructures. © 2014 Elsevier B.V. All rights reserved.

Journal of Alloys and Compounds

Manipulating aggregation of CuO nanoparticles: Correlation between morphology and optical properties

We report the preparation of polycrystalline GaN films on glass substrates by modified activated reactive evaporation (MARE). In this technique, substrates are kept on cathode instead of ground electrode and hence subjected to low-energy nitrogen ion bombardment. With increase in rf power, nitrogen to gallium (N/Ga) ratio in the films and film resistivity monotonically increases whereas oxygen impurity reduces. All GaN films are of wurtzite structure and films grown at higher powers have preferred orientation towards c-axis. Crystalline quality improves with increase in rf power up to ∼150 W and thereafter it degrades. Improvement in crystalline quality can be attributed to Ga/N stoichiometry and reduction in oxygen concentration, whereas degradation can be attributed to the presence of point defects due to excess nitrogen and nitrogen ion bombardment. Optical emission spectroscopy (OES) is used to investigate the relative concentration of excited species during GaN growth. MARE offers a technique to grow low-temperature group III nitride semiconductors. A high deposition rate (4.3 μm/h) was achieved in MARE for growing polycrystalline films on relatively inexpensive substrates. MARE is relatively less complex and offers a viable alternative for large scale growth for polycrystalline GaN thin films. © 2009.

Journal of Crystal Growth

Low-temperature growth of polycrystalline GaN films using modified activated reactive evaporation

Progress in Materials Science

CuO nanostructures: Synthesis, characterization, growth mechanisms, fundamental properties, and applications

Materials Science in Semiconductor Processing

Physical properties of nanocrystalline CuO thin films prepared by the SILAR method

Formation of CuO on thermal and laser-induced oxidation of Cu3N thin films prepared by modified activated reactive evaporation

Journal	Data powered by TypesetApplied Physics A: Materials Science and Processing
Publisher	Data powered by TypesetSpringer Verlag
ISSN	09478396
Open Access	No