N. D. Md Sin

Improvement sensitivity humidity sensor based on ZnO/SnO2 cubic structure

ZnO nanorod, SnO2 nanoparticle and ZnO/SnO2 cubic structure were prepared using sol-gel immersion method. These three structures had been growth on top sputtered ZnO thin film. The surface morphology of all thin film were characterized using field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectroscopy (EDX). The prepared thin films were fabricated for humidity sensor application. The composite sensor ZnO/SnO2 cubic structure gave excellent sensitivity compare to ZnO nanorod and SnO2 nanoparticle. The improvement sensitivities of ZnO/SnO2 cubic structure were 22.5 times from ratio of R40RH% to R90RH% at 25°C. ZnO/SnO2 cubic structure had a great potential for humidity sensor application with good in repeatability and stability.

Structural properties of Al-doped ZnO thin films deposited by Sol-Gel spin-coating method

Nanostructured Aluminium (Al) doped zinc oxide (ZnO) has been prepared using sol-gel spin-coating method. The annealing temperature was varied and the effect on the surface characteristic of ZnO thin film was studied. The surface topography and morphology of the thin films were characterised using X-ray Diffractometer (XRD), Atomic Force Microscopy (AFM) and Field Emission Scanning Electron Microscopy (FESEM). The paper reveals the effect of annealing temperature and Al doping on the surface characteristic of ZnO thin film. At optimum annealing temperature with doping, the ZnO thin film was observed to have more porous structure with smaller grain size which might enhance the gas sensing performance.

Structure transformation of ZnO thin films properties influenced by substrate temperature deposited by magnetron sputtering

The structure transformation of ZnO thin films properties influenced by substrate temperature deposited by RF Magnetron Sputtering is presented. This project has been focused on electrical, optical and structural properties of ZnO thin films. The effect of variation substrate temperature at 200°C~500°C on the ZnO thin films have been investigated. The thin films were examined using two point probe current-voltage (I-V) measurement (Keithley 2400), UV-Vis-NIR spectrophotometer, field emmision scanning electron microscopy (FESEM) (JEOL JSM 7600F) and atomic force microscope (AFM) (Park System XE-100). ZnO thin films were prepared at 200 watt by a RF magnetron sputtering using ZnO target using glass as the substrate. The IV measurement indicated as the substrate temperature increase, the conductivity of ZnO thin film increase. All films have show high UV absorption properties using UV-VIS spectrophotometer (JASCO 670). The root means square (rms) roughness for ZnO thin film were about (<;8nm) was measured using AFM. The image form FESEM observed that transformation of structure started to change at high temperature (400~500°C).

Structural and optical properties of N-doped ZnO nanorod arrays prepared using sol-gel immersion method

Nitrogen (N)-doped zinc oxide (ZnO) nanorod arrays were synthesized on aluminium (Al)-doped ZnO seed layer catalyst using sol-gel immersion method. The XRD analysis showed that the increment in crystallite sizes and lattice parameters while the strain/stress of the films reduced when the concentration increased. The FESEM image revealed that the nanorods exhibit hexagonal shape. The average diameters of nanorods have increased from 150 nm (undoped) to 230 nm (3 at.%). The N-doped ZnO nanorod arrays also displayed good transmittance properties at visible region.

Application of metaheuristic algorithms in nano-process parameter optimization

This paper presents the adaptation of Genetic Algorithm (GA), Particle Swarm Optimization (PSO) and Gravitational Search Algorithm (GSA) in solving a nano-process parameter optimization problem. The nano-process in this study is involving the RF magnetron sputtering process. The performances of the algorithms are compared in this optimization problem. The performance of GA, PSO and GSA is evaluated based on the fitness of the optimized parameter combination, processing times and the results from comparison with the actual laboratory experiments. The purpose of this computational experiment is to obtain the most optimized parameter combination among the selected datasets. The source material used in this study is zinc oxide (ZnO) and the most optimized combination of the process parameters is expected to produce the desirable nanostructured ZnO thin films electrical properties. The results have shown that GA could perform better than PSO and GSA by generating higher fitness values in 30 trial runs. However, GA has obtained the slowest execution time among the three algorithms. In this study, GSA has also produced an acceptable and promising result with faster execution time. When compared with the actual laboratory experiment, GA and GSA have generated more accurate optimization results. In terms of convergence of the algorithms, GA and GSA have shown more stable convergence compared to PSO. This study has shown that metaheuristic techniques are promising and reliable to be applied in solving this process parameter optimization problem.

Computational intelligence technique in optimization of nano-process deposition parameters

This paper is focusing on the RF magnetron sputtering process; a physical vapor deposition technique which is widely used in the thin film production. This process requires the optimized combination of deposition parameters in order to obtain the desirable thin film. This research is proposing gravitational search algorithm (GSA) technique in solving the RF magnetron sputtering deposition parameters optimization problem. In this research, the optimized parameter combination is expected to produce the desirable electrical and optical properties of the thin film. The performance of GSA in this research was compared with that of PSO and GA. Based on the overall result, the thin film that has been deposited based on GSA optimized parameter combination has generated the best electrical and optical properties results among others. This computational experiment is expected to overcome the problem of having to conduct repetitive laboratory experiments in order to obtain the most optimized parameter combination. Thus, the adaptation of computational intelligence into this problem could offer a more efficient and productive way of depositing quality thin film.

Structural properties of ZnO/SnO2-composite-nanorod deposited using thermal chemical vapour deposition

In this work, we report on the effect of substrate temperatures on ZnO/SnO2 composite nanorods deposited by thermal chemical vapour deposition (CVD) onto a ZnO template layer. The substrate temperature varied from 200 ~ 600°C. The FESEM image reveals that the size of the thin film created by the ZnO/SnO2 composite nanorods decreased as the substrate temperature increased.

High Sensitivity Humidity Sensor Based on ZnSnO3 Composite Nanocube

The performance of nanocomposites semiconducting material used as a sensor is very much depending upon physical and chemical properties of the material. In this paper we address sensitivity of ZnSnO3 thin film deposited by hydrothermal deposition in terms of its behavior towards humidity variations. The electrical, optical and structural properties of ZnSnO3 thin film deposit at different volume of solvent (50 ml and 70 ml) grown by novel deposition of ZnSnO3hydrothermal with low temperature 95°C are also reviewed. The sensor performance of ZnSnO3 thin film prepared at 50 ml volume show high sensitivity towards humidity. Using FESEM it was noted that the nanocube of ZnSnO3 thin films growth on ZnO template with the size of nanocube is 100 to 140nm by varying the volume of the solvent.

Electrical conductivity characteristics of tin-doped Zinc Oxide thin film deposited using sol-gel immersion method

Tin-doped Zinc Oxide (Sn-doped ZnO) thin film has been deposited onto glass substrates using sol-gel immersion method. These thin films are grown at different doping concentrations. The electrical and structural characterizations of the undoped and doped films were carried out using current-voltage (IV) measurement and field emission scanning electron microscopy (FESEM). From this study, it is known that, electrical properties were influenced by varying the doping concentration. Conductivity of thin films was found to increase as the doping concentrations increased. Also indicates in this paper the surface morphology of the thin film.

Humidity sensor based on SnO 2 nanoparticle thin film synthesized by thermal chemical vapor deposition (CVD)

SnO2 nanoparticle thin film has been synthesized by using thermal chemical vapor deposition (CVD). The SnO2 nanoparticle were growth on Au catalyst at different substrate temperature (400~550oC). The surface morphology of were characterized using field emission scanning electron microscopy (FESEM). The sensing properties of SnO2 nanoparticle thin film were examined using two point probe current-voltage (I-V) measurement (Keithley 2400). Heavily distribution of SnO2 nanoparticle thin film at 450°C that reveal from the FESEM image. The higher sensitivity of SnO2 nanoparticle thin film was performed good at 450°C compare to others samples with 45 ratio. The response and recovery of SnO2 nanoparticle thin film were 485 s and 24s respectively.