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Zinc Sulphide thin films have been fabricated on glass substrate via chemical bath deposition technique using zinc acetate, thiourea as the precursor of zinc and sulfur and ammonia for varying pH. The X-Ray diffraction patterns indicate the nanocrytalline nature of the films with broadening of diffraction peaks. Effective Mass Approximation, Scherrer Method and Williamson-Hall plots have been employed for determining crystallite size. The calculated crystallite sizes correlate well with the estimated crystallite sizes from High Resolution Transmission Electron Microscopy images. The HRTEM images show clear lattice fringes of nanocrystallites overlapping each other with random orientations. The elastic properties such as lattice strain, stress and energy density of ZnS thin films have been calculated from the modified form of Williamson-Hall analysis namely Uniform Deformation Model, Uniform Stress Deformation Model, and Uniform Deformation Energy Density Model. The Scanning Electron Microscope images indicate the granular texture of synthesized ZnS thin film at pH 9.6 and coagulation of granules into larger one with increase of pH. The results reveal the obvious effect of ammonia concentration on the optical properties, crystallite size, elastic properties and morphology of the surface of the films.

An improved, easier, and cost-effective pentacene double-layer technique with better performance is proposed in this paper to enhance the air stability of the pentacene-based organic thin-film transistors (OTFTs). This paper will definitely help to solve the instability issue of pentacene-based OTFTs so that they can be used in long durable low-cost flexible organic display.

A new technique called a pentacene double layer is proposed in this paper to enhance the air stability of the pentacene-based OTFTs. A practically insulating amorphous layer of pentacene (P-II) deposited at very low substrate temperature is used as protective layer above the pentacene active layer (P-I) so that an encapsulation layer of SiO2 can be deposited without damaging the active layer. This technique reduced the probability of interaction of O2 and H2O with the active pentacene layer to zero during fabrication of the devices (multiple breakdown process), and hence can be fabricated without using nitrogen ambient chamber as a result the devices become highly cost effective.

We have investigated the pentacene based Organic Thin Film Transistors (OTFTs) with High-k Dielectric Nd2O3. Use of high dielectric constant (high-k) gate insulator Nd2O3 reduces the threshold voltage and sub threshold swing of the OTFTs. The calculated threshold voltage -2.2V and sub-threshold swing 1V/decade, current ON-OFF ratio is 1.7 × 10(4) and mobility is 0.13cm²/V.s. Pentacene film is deposited on Nd2O3 surface using two step deposition method. Deposited pentacene film is found poly crystalline in nature.

Tetracene thin film transistors with rare earth oxide (Nd 2 O 3 ) as gate dielectric is reported in this work. Rare earth oxide with high dielectric constant and low leakage current improve the performance of the organic thin film transistors (OTFTs). The fabricated tetracene OTFTs have shown good output characteristics with mobility 0.93x10 -4 cm 2 /V.s, ON-OFF ratio 3.3x10 2 , sub-threshold swing 0.06 V/decade and hole concentration 8.74x10 17 cm -3 . Keywords: Organic thin film transistors; Tetracene; Rare earth oxide; Trap density. © 2010 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. DOI: 10.3329/jsr.v2i2.4094 J. Sci. Res. 2 (2), 214-220 (2010)