Speciation and the nature of ZnO thin films from chemical bath deposition

Abstract

Thin films of monophasic crystalline hexagonal ZnO were deposited from solutions of zinc acetate in presence of ethane-1,2diamine and sodium hydroxide onto glass microscope slides and tin oxide coated glass. At least two distinct morphologies of ZnO were observed, depending on the deposition conditions, by scanning electron microscopy. The films deposited on glass slides were generally more adherent and of better morphology than those on the tin oxide substrate. Calculations on the speciation of zinc in the solution indicate that supersaturation of hydroxy species of zinc is an important factor controlling bath deposition; solutions which are kinetically unstable with respect to the formation of zinc hydroxide deposit ZnO films of the best quality. The bandgaps of these films were estimated to be 3.15 eV, on either substrate, by optical absorption.

Morphology Control of Metal Oxide Nanocrystals

“…Full sun efficiency of 1.5% is demonstrated in this study. O'Brien et al prepared specular ZnO films consisting of clumps of elongated triangular crystals 53 , small ZnO spherical clumps consisting of particles of ca. 100 nm 53 , ZnO films consisting of randomly rod-shaped particles of up to 1000 nm in length 53 , ZnO films consisting of very thin random rod-shaped particles of ca.…”

“…O'Brien et al prepared specular ZnO films consisting of clumps of elongated triangular crystals 53 , small ZnO spherical clumps consisting of particles of ca. 100 nm 53 , ZnO films consisting of randomly rod-shaped particles of up to 1000 nm in length 53 , ZnO films consisting of very thin random rod-shaped particles of ca. 1000 nm 53 and specular films consisting of flowers with well-formed triangle features 59 in aqueous solutions.…”

“…100 nm 53 , ZnO films consisting of randomly rod-shaped particles of up to 1000 nm in length 53 , ZnO films consisting of very thin random rod-shaped particles of ca. 1000 nm 53 and specular films consisting of flowers with well-formed triangle features 59 in aqueous solutions. However, ZnO films have usually been prepared on substrates 54,57,[60][61][62][63][64][65][66][67][68][69][70][71][72][73][74][75][76] , and in particular crystalline ZnO films having high c-axis orientation require expensive substrates such as single crystals or highly-functional substrates.…”

Nanofabrication of Metal Oxide Nanostructures in Aqueous Solutions

“…O'Brien et al prepared specular ZnO films consisting of clumps of elongated triangular crystals 53 , small ZnO spherical clumps consisting of particles of ca. 100 nm 53 , ZnO films consisting of randomly rod-shaped particles of up to 1000 nm in length 53 , ZnO films consisting of very thin random rod-shaped particles of ca. 1000 nm 53 and specular films consisting of flowers with well-formed triangle features 59 in aqueous solutions.…”

Temperature-dependent Photoluminescence Study on Aluminum-doped Nanocrystalline ZnO Thin Films by Sol-gel Dip-coating Method

“…Moreover, ZnO is a multifunctional semiconductor material that has been exploited for short-wavelength optoelectronic applications such as light-emitting diodes, laser diodes, photodetectors, etc.. 25 To enhance its optical properties, ZnO is commonly doped with Group III elements (B, In, Al, or Ga). ZnO thin films have been prepared by a variety of thinfilm deposition techniques, such as pulsed-laser deposition, 6 RF magnetron sputtering, 7 chemical vapor deposition, 8 spray pyrolysis, 9 chemical bath deposition, 10 and the sol-gel process. [11][12][13] Among the preparation techniques of ZnO thin films, the sol-gel process in combination with the dip-coating process offers the greatest possibility for low-cost small and large-area coating of ZnO thin films for technological applications.…”