Anomalous luminescence phenomena of indium-doped ZnO nanostructures grown on Si substrates by the hydrothermal method

Abstract

In recent years, zinc oxide (ZnO) has become one of the most popular research materials due to its unique properties and various applications. ZnO is an intrinsic semiconductor, with a wide bandgap (3.37 eV) and large exciton binding energy (60 meV) making it suitable for many optical applications. In this experiment, the simple hydrothermal method is used to grow indium-doped ZnO nanostructures on a silicon wafer, which are then annealed at different temperatures (400°C to 1,000°C) in an abundant oxygen atmosphere. This study discusses the surface structure and optical characteristic of ZnO nanomaterials. The structure of the ZnO nanostructures is analyzed by X-ray diffraction, the superficial state by scanning electron microscopy, and the optical measurements which are carried out using the temperature-dependent photoluminescence (PL) spectra. In this study, we discuss the broad peak energy of the yellow-orange emission which shows tendency towards a blueshift with the temperature increase in the PL spectra. This differs from other common semiconductors which have an increase in their peak energy of deep-level emission along with measurement temperature.

Highly concentrated IZO colloidal nanocrystals with blue/orange/red three-colors emission

“…That orange emission is useful for biological application and DNA studies [19].The orange emission centered at 600-630 nm which can be attributed to transition from conductive band to native deep level defects in lattice, namely O i , or zinc vacancy complex. In addition, the formed trapping of a charge carrier on the nanocrystals surfaces, to an orange photoluminescence or a non-radiative recombination can be observed [20]. The presence of In 3+ ions lead to change in the density of lattice defects of ZnO nanostructured samples.…”

Effect of NaOH molar concentration on optical and ferroelectric properties of ZnO nanostructures

“…The emission spectra at the excitation wavelength 325 nm give four peaks at 385, 469, 657 and 770 nm, respectively. The peak of UV emission at 385 nm can be attributed to the near band edge (NBE) emission of ZnO and originated by the recombination of the free exciton transition from the localized level below the conduction bandto the valence band[41][42]. In addition to UV emission, there are also one or more emission bands in the visible spectral region.…”

Electrochemical route to the synthesis of ZnO microstructures: its nestlike structure and holding of Ag particles

“…Since Yang observed the room temperature UV lasing from ZnO nanorod arrays [4], much effort has been devoted to tailor the morphology and size to optimize the optical properties. As a result, various ZnO nanostructures, including nanowires [5-7], nanotubes [8,9], nanobelts [10], nanoflowers [11], nanospheres [12], nanobowls [13], dandelions [14], cages [15], and shells [16,17] have been obtained by solid-vapor phase growth [18], microemulation [19], and hydrothermal methods [20,21]. Hereunto, nanobowls, nanocups, or nanodishes have attracted much interest because they have been envisaged to further contain nanoparticles [22] and immobilize biomolecules [23,24].…”