Effects of Thickness Variation on Properties of ZnO Thin Films Grown by Pulsed Laser Deposition

Abstract

A series of ZnO films with various thicknesses were prepared on (0001) sapphire substrate by pulsed laser deposition (PLD). Scanning electron microscopy (SEM) and x-ray diffraction (XRD) analysis were utilized to investigate the effects of thickness variation on the surface morphology and the crystallinity. The electrical and optical properties of the films were also investigated as a function of the film thickness. It was found that the crystalline quality, electrical and optical properties of the films depended on the film thickness and were improved with increasing the film thickness. This is attributed to the fact that the films thinner than 4000A are under the severe misfit strain, which decreases with increasing the film thickness further.

Effect of sol concentration on the properties of ZnO thin films prepared by sol–gel technique

“…3(b). This is in conformity with the earlier results [17,20]. As the concentration increases, amount of solute (i.e.…”

“…2(b) shows the full width at half maximum (FWHM) values of the films with the variation of sol concentration. The FWHM value decreases quasi linearly as the concentration increases indicating a better crystallinity of the films with higher sol concentration [20]. The XRD data shows that the position of (0 0 2) diffraction peak shifts towards higher angle indicating that the c-axis value of the ZnO thin films decreases with increase in the sol concentration.…”

“…Table 1 shows that both the dark current and the photocurrent of the film with 0.05 M sol is maximum indicating maximum number of charge carriers available in that film for the conduction process. It has been found that the number of defect increases with increase in the strain in the film [20,33]. Further, the increase in the defects causes an increase in the carrier concentrations [23].…”

ZnO Metal-Semiconductor-Metal UV Photodetectors on PPC Plastic with Various Metal Contacts

“…Thus we can conclude that the film deposited on PPC plastic is nanostructured crystal. This finding is in agreement with the result reported by Myoung et al (Myoung et al, 2002).…”

Structural and optical characterization of pure ZnO films synthesised by thermal annealing on GaSb single crystals

“…ZnO films have been deposited by using a variety of methods like SOL-GEL [6], spray pyrolysis [7], magnetron sputtering [8], pulsed laser deposition (PLD) [9], molecular beam epitaxy (MBE) [10] and metal-organic chemical vapour deposition (MOCVD) [11]. In addition, it has been reported recently [12] the deposition of high quality ZnO films on Si substrates by metal Zn evaporation and post annealing (oxidation) in ambient conditions at low temperature (410 ºC), with obvious advantages like low cost, inexpensive equipment, and the inherent simplicity of the technique.…”