Effects of Doping with Al, Ga, and In on Structural and Optical Properties of ZnO Nanorods Grown by Hydrothermal Method

Abstract

The structural and optical properties of the ZnO, Al-doped ZnO, Ga-doped ZnO, and In-doped ZnO nanorods were investigated using field-emission scanning electron microscopy, X-ray diffraction, photoluminescence (PL) and ultraviolet-visible spectroscopy. All the nanorods grew with good alignment on the ZnO seed layers and the ZnO nanorod dimensions could be controlled by the addition of the various dopants. For instance, the diameter of the nanorods decreased with increasing atomic number of the dopants. The ratio between the nearband-edge emission (NBE) and the deep-level emission (DLE) intensities (I NBE /I DLE ) obtained by PL gradually decreased because the DLE intensity from the nanorods gradually increased with increase in the atomic number of the dopants. We found that the dopants affected the structural and optical properties of the ZnO nanorods including their dimensions, lattice constants, residual stresses, bond lengths, PL properties, transmittance values, optical band gaps, and Urbach energies.

Investigation of characteristics of ZnO:Ga nanocrystalline thin films with varying dopant content

“…Also, these values are in an acceptable range as measured by other researchers. For example, Kim et al [31] investigated Al, Ga and In doped ZnO, prepared by the hydrothermal method, and their results were a¼ 3.18 Å and c¼5.20 Å. Additionally, Hong et al [32] reported that the lattice parameters of ZnO were a¼3.25 Å and c¼5.12 Å, which are very close to our study. When small radius ions such as Al 3 þ and Ga 3 þ enter the ZnO crystal structure, the structure is affected by the Al 3 þ or Ga 3 þ doping.…”

Dye-modified ZnO nanohybrids: optical properties of the potential solar cell nanocomposites

“…However, optical band gaps of the ZnO-laali and ZnO-zobo shifted towards the red and blue regions, respectively, when compared with that of ordinary ZnO nanoparticle. Consequently, the optical band gaps changed proportionally with shift in absorption edge [29].…”

Enhanced photovoltaic performance of ZnO nanorod-based dye-sensitized solar cells by using Ga doped ZnO seed layer

“…While the size of grains decrease gradually as the Ga dopant concentration increase from 1 at.% to 4 at.%, which is due to increasing the Ga dopant content that could reduce the crystallite size, thus lead to the growth of smaller nanorods. Besides, the length of ZnO nanorod arrays increases as Ga concentration rises due to the rapid growth rate of ZnO nanorods along the c-axis [20]. It is well known that the growth process of ZnO nanorods shows the epitaxy growth along the surface of the seeds.…”