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Among all transition metal dichalcogenides (TMDs), MoS2 shows very unique conducting and optoelectronic properties, which makes it the most suitable material for fabricating real-time sensors and atomically thin transistors. By chemical modifications, the MoS2 can be made more useful in the field of various gas sensors, biosensors, and optoelectronic devices. In this study we present a novel facile method to grow 2-D MoS2 thin films by electrochemical deposition technique. We have successfully grown MoS2 thin films on ITO substrates through functionalization of MoS2 nano-flakes in the presence of monochloroacetic acid (MCA). The functionalization of trigonal prismatic MoS2 flakes with carboxyl group was achieved through sonication of MoS2 solution in DI water in the presence of MCA and KOH. Due to weak van der Walls force between the sulphur-sulphur layers of MoS2 flake, ultrasonic vibrations can easily intercalate the MoS2 flakes, creating sulphur vacancies at the two outer side surfaces and further saturated by Cl atoms of the MCA, forming MoS2-COOH composites. The as grown composites were then driven through linear sweep voltammetry on an ITO glass plate to form MoS2 thin film by controlling the sweeping cycles. The growth of the thin film was confirmed by the cyclic voltammetric current responses, which show the corresponding change in oxidation peak currents after the deposition of MoS2 thin film on the ITO substrates. It was further observed that the charge transfer decreases with the increase in thickness of the thin film as expected from the thick MoS2 semiconductor. These 2-D MoS2 can be of immense use in designing new type of real-time semiconducting biosensors, gas and electrochemical sensors, and atomically thin 2-D transistors. [ABSTRACT FROM AUTHOR]

In this work, we report fabrication of high quality visible light photo-detector based on nano-crystalline cadmium sulfide (CdS) thin film deposited on glass substrate using spray pyrolysis technique. Structural, morphological and chemical analysis of the film confirms uniform coating of sulfur deficient nano-crystalline CdS thin film with∼30 nm crystallites. Finger electrodes were made on the film using Ag paste. Photo-detection property of nano-crystalline CdS thin films was tested under visible light illumination and the response of incident light in terms of photo-current was monitored when exposed at various light intensities ranging from 5 to 320 mW/cm2. The fabricated device showed highly sensitive and repeatable photo-detection at 10 V for low power 5 mW/cm2 light. Time response measurements at different wavelength show ultra-fast response (0.67 ms) and decay (0.86 ms) time and high photo sensitivity at low bias voltage. [ABSTRACT FROM AUTHOR]

In this paper, we report an extremely low cost and highly efficient method for fabrication of visible light photo-detector using nano-crystalline lead sulfide (PbS) thin film. The film was fabricated on 300 GSM paper via spray pyrolysis technique at 100 °C. Structural and morphological analysis of the film confirms the nano-crystalline nature of PbS with size ∼ 50 nm and uniform coating of PbS on paper. Photo-detector devices are prepared by drawing contacts using 4B pencil on the film by keeping a gap of 1 mm between electrodes. Photo-detection property of a nano-crystalline PbS thin film under visible light illumination show linear I-V suggesting low resistive contact between graphite electrode and PbS film. The photo-sensitivity measurements reveal excellent sensitivity of ∼103 at 20 V. For this graphite/nano- PbS/paper photo-detector, the best rise and decay time is observed to be 7 and 16 ms, respectively. This simple and low cost fabrication method results in highly stable and sensitive photo-detectors device, which have fast response and decay time. [ABSTRACT FROM AUTHOR]

In this work, nickel oxide thin films have been successfully deposited with a simple and low-cost spin coating method and annealed at 250⁰C. The structural and optical characterization of the NiO thin films was carried out using XRD, SEM, EDAX and UV-visible spectrophotometer. XRD pattern shows that all the prepared samples are in cubic structure and well-matched with JCPDS. From SEM, it is seen that all the films are uniform. From the transmittance spectra, the prepared samples are highly transparent, and the optical energy band gap was calculated from absorption spectra. These prepared samples were tested using static gas sensing set up to detect different reducing analyte gases including ammonia towards various ppm at room temperature. Ammonia is found to be good selective and highly sensitive. Response time and recovery time of the fabricated sensor were calculated and reported. [ABSTRACT FROM AUTHOR]

We present a study of variation in the dielectric properties of polymeric blend films of polyacrylamide (PAM)/Polyvinylalcohol (PVA). Initially, the PAM and PVA were used to obtain apolymeric blend solution in distilled water. Preparation of blended films was conducted by a drying process. Films of pure PAM, pure PVA and blend films (w/w%) were characterizedby X-ray diffraction (XRD) and scanning electron microscopy (SEM). The characterizations revealed proper trends for the films depending upon weight percent (PAM: PVA: 20:80, 40:60, 60:40, 80:20). Variations in their dielectric property were investigated by use of a LCR (inductor capacitor resistor) meter. [ABSTRACT FROM AUTHOR]

Modulation in resistance switching characteristics of TiO2 thin film fabricated on aluminum substrate is investigated under optical illumination. The average thickness of TiO2 thin film is about 200 nm. The current–voltage characteristics of the Pt/TiO2/Al structure show a good rectifying property with unipolar resistive switching behavior. This resistive switching behavior is observed to be modulated by optical illumination. Photo-carriers generated during optical illumination shifts the set and reset voltage to lower values. This study is helpful for exploring optical effect in metal oxides as multifunctional materials and its applications in non-volatile memory devices. [ABSTRACT FROM AUTHOR]

In the present work, ZnS/Graphene nanocomposite is prepared by solution mixing and sonication method. The thin films are prepared with homemade chemical spray pyrolysis system (CSP) by the colloidal spray coating method. ZnS/graphene nanocomposite thin film fabricated at the substrate temperature of 350°C. Uniform, adherent, highly crystalline, and transparent thin film obtained. The films characterised by UV-Visible spectroscopy, Photoluminescence, X-Ray diffraction (XRD), Energy dispersive spectroscopy (EDS), and scanning electron microscopy (SEM). The absorption spectrum of composite shows the blue shift in the absorption peak as compared to intrinsic ZnS thin film. The bandgap increased from 4.1eV (intrinsic ZnS at substrate temperature 350°C) to 4.9eV (ZnS/graphene composite at substrate temperature 350°C). The XRD and EDS analysis confirm the composite formation and purity of the samples. The SEM images show the uniformity of thin films with granules agglomerated structures. [ABSTRACT FROM AUTHOR]

We present systematic investigations of tuning magnetic anisotropy, domain structure, magnetic, structural and electrical transport properties of Fe1-xNix thin films. All the films were prepared by DC magnetron sputtering directly on Si (100) substrate maintained at different substrate temperatures (TS). Fe1-xNix films deposited at ambient temperature exhibit disordered structure. With increasing TS, the degree of L10 ordering enhanced up to 250°C and then decreased due to the formation of A1 phase. As a result, the average surface roughness increased and consequently the electrical resistivity decreased with increasing TS. Saturation magnetization (MS) and anisotropy energy (Ku) increased progressively with increasing Fe content and exhibited a maximum of 0.91 T and 0.52 MJ/m3, respectively, for Fe51Ni49 thin films prepared at TS = 250 °C. Magnetic domain studies confirmed the existence of in-plane niaxial magnetic anisotropy in L10 ordered FeNi films. [ABSTRACT FROM AUTHOR]