Photoluminescence of ZnO layers grown on opals by chemical deposition from zinc nitrate solution

Abstract

The emission from ZnO layers grown on the surface of bulk opals using chemical deposition is studied under excitation by the 351.1 nm line of an Ar + laser at different excitation power densities and temperatures. The emission spectrum exhibits narrow photoluminescence (PL) bands associated with the recombination of bound and free excitons as well a relatively broad band around 3.31 eV. The width of the excitonic lines (2-3 meV) along with their energy position are indicative of the high quality and strain-free state of the layer. The origin of the 3.31 eV PL band is discussed in connection with its dependence upon the excitation power density and temperature.

Optical and sensory properties of ZnO nanofibrous layers grown by magnetron sputtering

“…2a) is dominated by the donor bound exciton emission (D 0 X) at 3.353 eV and 3.363 eV as well as by an emission band at 3.311 eV with phonon LO replica. A similar band at 3.311 eV was previously attributed to donor-acceptor pair recombination (DA) [14][15][16][17][18]. Most probably, a very shallow donor and a deeper acceptor are involved in this DA transition.…”

Selective hydrogen gas nanosensor using individual ZnO nanowire with fast response at room temperature

“…Usually, the red and the green luminescence is attributed to different structural defects such as oxygen vacancy (V O ), zinc vacancy (V Zn ) or a complex defect involving interstitial zinc (Zn i ) and interstitial oxygen (O i ) [35][36][37][38][39][40][41][42][43][44]. The low intensity of the visible emission as compared to the near band-edge one is an indication of a low concentration of defects.…”

Luminescence properties of a ZnO–In 2 O 3 composite

“…With increasing temperature the 3.31 eV band moves towards the band gap as shown by arrows in Fig. 4, the rate of approach being close to 2kT which is characteristic for recombination of free carriers via donor-acceptor pairs [12].…”

“…Apart from excitonic emission a weaker PL band centered at 3.310 eV with the phonon replica at 3.238 eV is also observed in the spectrum. This is one of commonly occurring bands in high quality ZnO epitaxial films, nano-crystalline thin films, and ZnO rods (see, for instance, [12] and refs therein). The dependence of this band upon temperature and excitation power density suggests its connection with the radiative recombination of free carriers via donor-acceptor pairs (DAP), in accordance with previous assumption [13].…”