Abstract

INTRODUCTIONExtensive research has been carried out on the deposition and characterization of polycrystalline thin films by several researchers . These materials are used in optical instruments, solar cells, telecommunications terminals, in-vehicle equipment, traffic lights, magnetic films, diamond films, microelectronic devices, solar selective coatings, sensor devices, optical mass memories and superconducting films. In recent years, binary semiconductor material such as zinc telluride has been studied by many scientists. Recent investigations have shown that zinc telluride thin films show absorption in the spectrum range from visible to near infrared (as widely reported in the literature). The II-VI (ZnTe) compound semiconductors have a direct transition at 2.26 eV. Therefore, ZnTe is capable of green light emission at 550 nm, i.e. in spectral region corresponding to the maximum sensitivity of the human eye. This makes ZnTe an appealing candidate for the production of bright light-emitting diodes and diode lasers. There are several reports available on the growth of zinc telluride thin films by different deposition methods such as electro-deposition method [33][34][35] Zinc telluride thin films can be used in a large variety of applications such as optoelectronics and microelectronics tools. In this paper, the growth of ZnTe films prepared by electrodeposition, thermal evaporation and closed space sublimation method with various precursors and some its physical properties of obtained zinc telluride films are discussed.

No abstract

Ternary compounds such as Cu4SnS4 thin films can be deposited onto glass substrates by various deposition methods: electrodeposition, chemical bath deposition, successive ionic layer adsorption and reaction, and evaporation techniques. Cu4SnS4 films could be used in solar cell applications because of their suitable band gap and large absorption coefficient. This paper reviews previous researches on Cu4SnS4 thin films. X-ray diffraction showed that the obtained films are orthorhombic in structure and polycrystalline in nature. Cu4SnS4 films exhibited p-type electrical conductivity and indicated band gap values in the range of 0.93 to 1.84eV.

Thin film technology is getting huge attention across the world due to its wide applications. Deposition of thin films involves creation, transportation and condensation of target materials with thickness varying from few nanometers to several microns onto the substrate. This review will highlight thin film depositing techniques which consist of non-vacuum and vacuum based deposition method. Besides this, thin films and their applications in gas sensing and corrosion protection have also been discussed.

Oil palm is known as Elaeis guineensis, found in Africa, South East Asia and China. Oil palm shell is used to prepare activated carbon because of high carbon content, high surface area, highly developed porosity and low price. During the physical activation, carbonization occurs in order to create porosity in the raw material. Literature review indicated that carbon material was impregnated with chemical agents such as phosphoric acid, potassium hydroxide, sulphuric acid, sodium hydroxide and zinc chloride in chemical activation process. Experimental results showed that the obtained activated carbon was used in hydrogen storage purpose, supercapacitor, gases and liquid phase adsorption process. On the other hand, oil palm shell was used in manufacturing lightweight concrete because of lighter and will not produce toxic substance. The bulk density and compressive strength of oil palm shell-based concrete were 500 -600 kg/m 3 and more than 25 MPa, respectively.

No abstract

No abstract