The structural and optical properties of thin lead oxide films were studied. Thin films were prepared by reactive dc magnetron sputtering of lead (Pb) targets in an Ar/O2 mixture. The structure has been determined by x-ray diffraction measurements, which show that crystalline lead oxide films of different composition (PbO, PbO1.44, Pb2O3, and PbO2) have been formed upon increasing oxygen flow (partial pressure). This result is confirmed by Raman spectroscopy. The effect of postdeposition annealing on the structural properties of PbO films reveals that the film structure is governed by both energetics and kinetics. X-ray reflectivity measurements were used to determine the thickness, density, and roughness of the films. The calculated film density values are almost equal to the bulk density of the material, showing that compact, nearly void free films are formed. The optical properties of the films have been studied from the reflectance and transmittance spectra recorded by optical spectroscopy measurement...

Structural and optical properties of thin lead oxide films produced by reactive direct current magnetron sputtering

In recent years, layered black phosphorus (BP) nanostructures have demonstrated great potential applications in transistors, optoelectronics and logic devices due to their excellent intrinsic electronic and optoelectronic properties. However, the high cost of BP and its rapid degradation upon exposure to ambient conditions turn out to be the two critical bottlenecks hampering practical applications. With the development of semiconductors in leaps and bounds, a new wave of exploration of black phosphorus analogues (BPAs), whose excellent optoelectronic performance and high chemical stability under ambient conditions unveil great promise for practical applications, has emerged. This review presents the synthesis and morphology control of emerging BPAs, the latest progress in understanding the fundamental properties of BPA nanostructures, and the recent advances in constructing prototypical high-performance BPA-based devices for practical applications. Finally, the prospects for future research, application opportunities, and the accompanying challenges of BPAs are discussed.

Emerging black phosphorus analogue nanomaterials for high-performance device applications

Role of annealing temperatures on structure polymorphism, linear and nonlinear optical properties of nanostructure lead dioxide thin films

Silver deposited carboxymethyl chitosan-grafted magnetic nanoparticles as dual action deliverable antimicrobial materials.

Thin films of lead oxide were synthesized by cost effective spray pyrolysis technique at different substrate temperatures on glass substrates. Effect of substrate temperature on the growth mechanism and physical properties of the films was investigated. All the films were polycrystalline in nature with tetragonal structure corresponding to α-PbO. The films coated at 225 °C and 275 °C were (1 0 1) oriented, while the films deposited at 325 °C and 375 °C were (0 0 2) oriented. Above 375 °C, the pure tetragonal nature deteriorated and the peaks corresponding to orthorhombic phase were observed. The band gap value was found to be in the range of 2.3 to 2.62 eV. All the films had a resistivity of the order of 103 ohm-cm. A minimum resistivity of 0.0191 × 103 ohm-cm was obtained for the film coated at 325 °C. The activation energy increased with increase in substrate temperature.

/pdf/role-of-substrate-temperature-on-the-growth-mechanism-and-58a9akdg2g.pdf

Role of substrate temperature on the growth mechanism and physical properties of spray deposited lead oxide thin films

The thermal sensitization process for the enhancement of photoconductivity in tetragonal lead monoxide has been investigated. At a critical annealing temperature the photosensitivity has been found to have a maximum value (≅5×102) while the conductivity is observed to have a minimum value (≅10−10Ω cm). The transient response of the photocurrent exhibits an overshoot, the height of which is strongly dependent on the annealing temperature. These and other findings have been explained on the basis of sensitization due to the creation of two types of centres in the material.

Sensitization of photoconductivity in tetragonal lead monoxide

Photopolarization process in orthorhombic lead monoxide

The charging and discharging characteristics of corona charged polyvinyl acetate films are investigated as a function of thickness. The saturation potential at constant corona field is found to vary with film thickness in a parabolic manner. The rise and decay transients of the surface charge are found to follow closely the theoretical expressions derived on the basis of space charge formation in the bulk of the polymer during corona charging.



Die Aufladungs- und Entladungscharakteristiken von Polyvinylazetatschichten, die in einer Koronaentladung aufgeladen werden, werden als Funktion der Filmdicke untersucht. Das Sattigungspotential bei konstantem Koronafeld variiert parabolisch mit der Filmdicke. Das An- und Ab- klingen der Oberflachenladung befolgt sehr gut die theoretischen Ausdrucke fur den Aufbau von Raumladungen im Volumen des Polymers wahrend der Koronaaufladung.

Surface charge decay characteristics in polyvinyl acetate films

The charge decay characteristics of selenium photoreceptors sensitized by thin metal-free phthalocyanine films are investigated using xerographic discharge technique. The rate of surface charge decay in the dark is found to be dependent on the initial charging conditions. The discharge characteristics seem to follow a U1/2 ∝ lg t type of relation. These and other observations are explained on the basis of field assisted detrapping of carriers in the photoreceptor.



Die Abklingcharakteristiken der Ladung von Selenphotoempfangern, die durch dunne, metallfreie Phthalocyanin-Schichten sensibilisiert wurden, werden mittels xerographischer Entladungstechnik untersucht. Die Abklinggeschwindigkeit der Oberflachenladung im Dunklen ist abhangig von den Anfangsbedingungen der Aufladung. Die Entladungscharakteristiken scheinen einer U1/2 ∝ lg t-Beziehung zu folgen. Diese und andere Beobachtungen werden auf der Grundlage von feldassistiertem Detrapping von Ladungstragern im Photoempfanger erklart.

S. Radhakrishnan

Papers

Sensitization of photoconductivity in tetragonal lead monoxide

Photopolarization process in orthorhombic lead monoxide

Surface charge decay characteristics in polyvinyl acetate films

Electronic conduction in dye‐sensitized selenium films