Physical properties of metal-doped zinc oxide films for surface acoustic wave application

Abstract

Metal-doped ZnO [MZO] thin films show changes of the following properties by a dopant. First, group III element (Al, In, Ga)-doped ZnO thin films have a high conductivity having an n-type semiconductor characteristic. Second, group I element (Li, Na, K)-doped ZnO thin films have high resistivity due to a dopant that accepts a carrier. The metal-doped ZnO (M = Li, Ag) films were prepared by radio frequency magnetron sputtering on glass substrates with the MZO targets. We investigated on the optical and electrical properties of the as-sputtered MZO films as dependences on the doping contents in the targets. All the MZO films had shown a preferred orientation in the [002] direction. As the quantity and the variety of metal dopants were changed, the crystallinity and the transmittance, as well as optical band gap were changed. The electrical resistivity was also changed with changing metal doping amounts and kinds of dopants. An epitaxial Li-doped ZnO film has a high resistivity and very smooth surface; it will have the most optimum conditions which can be used for the piezoelectric devices.

Piezoelectric and opto-electrical properties of silver-doped ZnO nanorods synthesized by low temperature aqueous chemical method

“…Our optical and structural results are consistent and similar to those reported in Ref. 17, nevertheless, we have not observed any change of morphology of Ag doped ZnO nanorods.…”

“…28 On the other hand, in ZnO thin films, the crystalline quality decreased considerably with increasing Ag atom%. 17 By introducing a very small doping amount, the effect will be such that; this dopant addition distorts the unit cell of the ZnO crystal. If the doping level is further increased, there will be a high deformation of the crystalline structure, leading to loss of the symmetry and decreasing thereafter the piezo response.…”

“…Based on the surface roughness and the electrical resistivity, S-H Nam et al claimed that Ag doped ZnO thin films deposited by radio frequency magnetron sputtering are not appropriate for piezoelectric devices because the films have poor crystallinity and low resistivity; interestingly, they did not measured the piezoelectrical properties of their films. 17 Moreover, the published papers on Ag doped ZnO nanostructures are so far very limited. 18,19 Among the many possible ZnO nanostructures, well-aligned nanorods (NRs) have attracted increased interest for many applications.…”

A Study of Microstructural Models of Li-doped ZnO Ceramic for Piezoelectric Application

“…Chaari et al [14] synthesized ZnO bulk ceramic at various growth temperatures and observed that the alignment of the ZnO grains along the (100) plane was enhanced as the temperature increased. Ardyanian and Sedigh [15] showed that Li-doped ZnO has a polycrystalline wurtzite structure with a preferred orientation along the (002) plane, and observed shifts in the diffraction peak angle of 34.57° 2θ in pristine ZnO, among others... bordering on microstructure and structural properties [3,[16][17][18][19].…”

Formation of randomly dispersed pores in Ga-doped ZnO between Al2O3 and glass via promoted atomic diffusion: Experimental and computational study

“…The ZnO is a well-known transparent A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT 4 conducting oxide (TCO) that has been intensively studied for application in electronics, optoelectronics and laser technology [28,29] due to its remarkable properties such as wide band gap (3.37 eV) [30][31][32][33][34][35], high exciton binding energy (60 meV) [30][31][32][33] and strong green luminescence [35]. The group III-doped ZnO films have also received attention over the years [36][37][38][39][40][41][42] /GZO(400 nm)/Glass(0.7 mm) were annealed in a horizontal tube furnace at atmospheric pressure at a temperature of 800℃ for 5 hours to generate Kirkendall voids in GZO. X-ray diffraction was performed with a Cu Kα1 radiation ( = 1.5406 Å) for phase identification of all the deposited films.…”