Ghulam Ishaq Khan Institute of Engineering Sciences and Technology

About: Ghulam Ishaq Khan Institute of Engineering Sciences and Technology is a education organization based out in Topi, Pakistan. It is known for research contribution in the topics: Thin film & Quantum efficiency. The organization has 618 authors who have published 940 publications receiving 10674 citations.

Electrical Characteristics of A1/CNT/NiPc/PEPC/Ag Surface-Type Cell

Abstract: The blend of nickel phthalocyanine (NiPc) (2 wt. %) poly-N-epoxypropylcarbazole (PEPC), (1 wt. %) and carbon nano-tube (CNT) powder (2 wt. %) in benzole is deposited by drop-casting on glass substrates with pre-deposited metallic electrodes to fabricate Ag/CNT/NiPc/PEPC/A1 surface type cell. It is assumed that the high nonlinearity of the I — V characteristics is related to deep traps in the nano-scale depletion region in NiPc that is observed experimentally. The values of ideality factor and barrier height are determined from the I — V curve and they are found to be 8.4 and 1.05eV, respectively. The values of mobility and conductivity are calculated to be 7.94 × 10−8 cm/Vs and 3.5 × 10−6 Ω−1 cm−1. The values of ideality factor and series resistance are also calculated by using Cheung's functions, which are in good agreement with the values calculated from the I — V curve.

Investigation of optical and humidity-sensing properties of vanadyl phthalocyanine-derivative thin films

Abstract: In this study an active layer of Vanadyl 2,9,16,23-tetraphenoxy-29H,31H-phthalocyanine (VOPcPhO) has been employed in surface type humidity sensor. On top of preliminary deposited asymmetric metal electrodes, a VOPcPhO thin film was spun cast to obtain a surface type Al/VOPcPhO/Au sensor. The gap between the electrodes was 40 um. A solution of 30 mg/ml was deposited at 3000 rpm. The thickness of the VOPcPhO film was 150 nm. The capacitive effect of the sample was evaluated in the relative humidity range 0–87%RH, at room temperature. It was observed that the capacitance of the sensor increases 10 times under the effect of entire humidity range in the relative humidity level. The optical properties of VOPcPhO thin film were also investigated. The humidity-dependent capacitive properties make the sensor suitable for the application in the instruments used for environmental monitoring of humidity.

Predicting regularities in lattice constants of GdFeO3-type perovskites.

Abstract: A novel idea of employing genetic programming to obtain mathematical expressions representing the dependency of lattice constants (LC) on their atomic parameters is presented in this paper. The results obtained from simulations reveal that only two atomic parameters are sufficient for LC prediction of GdFeO3-type perovskites. In addition, an advantage of this approach is that there is no need to save any trained model as in the case of other existing machine-learning based approaches.

Fabrication of cost effective and high sensitivity resistive strain gauge using DIW technique

Abstract: Tremendous increase in the number of sold micro sensing units have been reported in recent years. This research presented a resistance strain gauge of conductive carbon paste printed on flexible substrate through Micro-dispensing direct write (MDDW) technique. A high resistive strain gauge is reported that can measure large mechanical deformation with higher sensitivity. The printed structure is the same as common for strain gauge. The electrical characterization is carried out followed by gauge factor (G.F) calculation. Besides formal testing for strain, the strain gauge sensitivity were tested towards humid and warm environment. Microscopic characterization is carried out for surface morphology and particle sizing. A strain gauge for tensile test application is also presented in this work. The research concluded with the fabrication of a low cost high gauge factor strain gauge with sensitivity towards humid and warm environment.

Effects of Residual Stress Distribution on Interfacial Adhesion of Magnetron Sputtered AlN and AlN/Al Nanostructured Coatings on a (100) Silicon Substrate.

Abstract: The present study investigated the influence of nanoscale residual stress depth gradients on the nano-mechanical behavior and adhesion energy of aluminium nitride (AlN) and Al/AlN sputtered thin films on a (100) silicon substrate. By using a focused ion beam (FIB) incremental ring-core method, the residual stress depth gradient was assessed in the films in comparison with standard curvature residual stress measurements. The adhesion energy was then quantified by using a nanoindentation-based model. Results showed that the addition of an aluminum layer gave rise to additional tensile stress at the coating/substrate interface, which can be explained in terms of the differences of thermal expansion coefficients with the silicon substrate. Therefore, the coatings without the Al layer showed better adhesion because of a more homogeneous compressive residual stress in comparison with the coating having the Al layer, even though both groups of coatings were produced under the same bias voltage. Results are discussed, and some general suggestions are made on the correlation between coating/substrate property combinations and the adhesion energy of multilayer stacks. The results suggested that the Al bond layer and inhomogeneous residual stresses negatively affected the adhesion of AlN to a substrate such as silicon.