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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.

In this report, we have studied the compositional dependence of structural, optical and electrical properties of polycrystalline In x Ga1−x N thin films grown by modified activated reactive evaporation. The growth was monitored by optical emission spectroscopy. The thickness of the films was in the range ~600–800 nm. The phase, crystallinity and composition of the films were determined by X-ray diffraction, Raman spectroscopy and energy dispersive X-ray analysis. The surface morphology was studied by atomic force microscopy. The band gaps of these films obtained from transmittance and photoluminescence measurements were found to vary from 1.88 to 3.22 eV. All the films show n-type conductivity. The carrier concentration was found to be decreasing with increase in gallium incorporation which is in good agreement with the free carrier absorption observed in transmittance spectra.

In the present work, InxGa1 - xN films with different indium compositions (x = 0.88, 0.63, 0.36 and 0.18) were prepared on glass substrates using a commercially viable technique known as modified activated reactive evaporation. Electrochemical impedance was used to investigate the anion sensing properties of these films for KCl, KI and KNO3 salt solutions of different molar concentrations. The anion sensing behaviour of InGaN films is attributed to the presence of high n-type background carrier concentration and positively charged surface donor states. The InGaN based anion sensors were found to have good sensitivity with faster response and recovery time. The film with x = 0.63 was found to have the highest sensitivity for all the anions due to the presence of more active surface area together with large number of surface donor states. � 2011 Elsevier B.V. All rights reserved.

Polycrystalline InxGa1-xN thin films were prepared by mixed source modified activated reactive evaporation (MARE) technique. The films were deposited at room temperature on glass substrates without any buffer layer. All the films crystallize in the hexagonal wurtzite structure. The indium concentration calculated from XRD peak shift using Vegard's law was found to be varying from 2% to 92%. The band gap varies from 1.72 eV to 3.2 eV for different indium compositions. The indium rich films have higher refractive indices as compared to the gallium rich films. The near infra-red absorption decreases with gallium incorporation into InN lattice which is mainly due to decrease in the free carrier concentration in the alloy system. This fact is further supported from Hall effect measurements. MARE turns out to be a promising technique to grow InxGa1-xN films over the entire composition range at room temperature. � 2011 Elsevier B.V. All rights reserved.

We report the role of charged species N2 + on the growth of GaN films by modified activated reactive evaporation MARE . In MARE technique, substrate is subjected to low energy nitrogen ion bombardment by keeping it in conjunction with the radio frequency cathode. The low energy ion irradiation contributes to the effective formation of GaN as well as in the drastic reduction of the oxygen impurity content by resputtering of the weakly bonded oxygen adatoms. Significant reduction in oxygen impurity can be achieved in the MARE by increasing the concentration of the charged species in the plasma. © 2010 The Electrochemical Society. DOI: 10.1149/1.3512991 All rights reserved.

Nano-crystalline c-axis oriented In xGa 1-xN (x=0.93, 0.63, 0.5, 0.36 and 0.18) thin films were prepared by modified activated reactive evaporation technique. Phase segregation was clearly observed for x=0.5 composition. Scanning electron microscopy images reveal the average grain size for all the films to be varying from 40 to 85nm. From, the absorption spectra the band gaps for the InGaN films were found to be varying from 1.89 to 2.92eV. Micro-Raman scattering at two different excitation energies (1.96 and 2.54eV) were used to study the phase separation and compositional fluctuations of InGaN layers across their thickness. All the spectra exhibit the characteristic A 1(LO) and E 2 (high) modes corresponding to hexagonal wurtzite structure for both the excitations. No appreciable change in the peak positions for the two excitations confirms the absence of any significant phase separation across the thickness of InGaN films with x=0.36 and 0.18 composition. However, for x=0.93 and 0.63 films, gallium rich minority phase could be detected with 1.96eV excitation. The changes in the area and FWHM of the two characteristic Raman peaks for different excitations are attributed to the increased structural defects across the sample depth and also to the near resonance effects. Copyright � 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

In the present work, we report the temperature dependent carrier transport properties of InxGa1-xN thin films in the entire composition range grown by modified activated reactive evaporation. The carrier transport in these degenerate semiconductors is controlled by impurity band conduction. A transition from metallic to semiconducting type resistivity was observed for indium rich films. The semiconducting behavior originates from electron-electron interaction and weak localization, whereas higher temperature scattering contributes to the metallic type resistivity. A transition of resistivity behavior from the quantum phenomena to the classical Arrhenius approach was observed for x 0.12 film. � 2011 American Institute of Physics.

We report the effect of rf power on the structural, optical and electrical properties of InN films grown by modified activated reactive evaporation. In this technique, the substrates were kept on the cathode instead of ground electrode. The films grown at higher rf power shows preferential c-axis orientations for both silicon and glass substrates. The films prepared at 100 W show best structural, electrical and optical properties. The c-axis lattice constant was found to decrease with increase in rf power which can be attributed to reduction in excess nitrogen in the films. The band gap decreases with increase in rf power due to Moss-Burstein shift. The decrease in carrier concentration and optical band gap with increase in rf power can also be related to excess nitrogen in the film. The Raman spectra shows a red shift in the A 1(LO) and E 2 (high) mode from the reported value. The possible origin of the present large band gap is due to Moss-Burstein shift. The new film growth method opens opportunities for integrating novel substrate materials with group III nitride technologies. � 2008 Elsevier B.V. All rights reserved.

We have investigated the temperature dependent carrier transport properties of nano-crystalline copper nitride thin films synthesized by modified activated reactive evaporation. The films, prepared in a Cu-rich growth condition are found to be highly disordered and the carrier transport in these films is mainly attributed to the impurity band conduction. We have observed that no single conduction mechanism is appropriate to elucidate the carrier transport in the entire temperature range of 20 - 300 K. Therefore, we have employed different conduction mechanisms in different temperature regimes. The carrier transport of the films in the low temperature regime (20 - 150 K) has been interpreted by implementing quantum correction to the conductivity. In the high temperature regime (200 - 300 K), the conduction mechanism has been successfully analyzed on the basis of Mott's variable range hopping mechanism. Furthermore, it can be predicted that copper ions present at the surface of the crystallites are responsible for the hopping conduction mechanism. � 2015 Author(s).