Similarities in photoluminescence in hafnia and zirconia induced by ultraviolet photons

Abstract

Articles you may be interested inTemperature dependent dielectric function in the near-infrared to vacuum-ultraviolet ultraviolet spectral range of alumina and yttria stabilized zirconia thin films Mechanisms of several photoluminescence bands in hafnium and zirconium silicates induced by ultraviolet photons J. Appl. Phys. 99, 094106 (2006); 10.1063/1.2199977Photoluminescence from polymer-like hydrogenated and nitrogenated amorphous carbon films Photoluminescence ͑PL͒ spectra induced by ultraviolet photons were measured for amorphous hafnia and zirconia deposited by plasma-enhanced chemical-vapor deposition ͑PECVD͒, amorphous hafnia deposited by pulse laser deposition, and crystalline yttria-stabilized zirconia. Two kinds of samples were prepared for both hafnia and zirconia deposited by PECVD using different source alkoxides in different deposition chambers. A PL peak was observed around 2.8 eV similarly in all hafnia and zirconia samples, irrespective of the difference in crystallinity, oxygen deficiency, source alkoxide, deposition method, or the substrate material. The decay profile of this PL is also similar in all the samples. These facts clearly show that neither impurities, oxygen vacancy, nor defects at the interface between the sample and the substrate are responsible for the PL. It is a luminescence inherent in hafnia and zirconia and is most likely due to radiative recombination between localized states at the band tails. When the samples were annealed in oxygen, a new PL peak appeared around 4.2 eV in all the amorphous samples. Its decay profile is also in common with these samples. Vacuum-ultraviolet absorption measurements and PL excitation measurements indicate that the 4.2-eV PL is excited due to the interband absorption.

Intrinsic and defect related luminescence in double oxide films of Al–Hf–O system under soft X-ray and VUV excitation

“…In principle, these PL results are consistent with XRD analysis data (see section 3.1), which shows amorphisation of films, when Al concentration is increased. Indeed, the PL emission bands in the low-energy region of 2.8 eV are typical for amorphous HfO x films [14,15,34].…”

“…3 (curve 2) confirms this result. It is known that in HfO 2 crystals with defects the PL spectra contain the low-energy luminescence bands the region of 2.8-3.1 eV, at the same time in such crystals the STE emission is quenched and this STE band is not detected in PL spectra [14,15]. (Figs.…”

“…The 2.8 eV emission band is associated with oxygen vacancies. The nature of a band at energies above 3 eV is not yet established [10][11][12][13][14][15]34]. According to these papers, the PL excitation spectrum of this 2.8 eV band contains a selective maximum at the energy of 5.2 eV.…”

“…Such control can be effectively performed by using the luminescent methods. In low-temperature photoluminescence (PL) spectra of HfO 2 crystals or films the emission band of defects can be detected in the region of 2.7-3.1 eV [13][14][15]. An UV intrinsic emission band of self-trapped excitons (STE) was observed in the region of 4.4 eV [7,8,9].…”

“…Oxygen vacancies are the most probable and spread defects responsible for high conductivity. Thus, the identification of oxygen vacancies in HfO 2 and their concentration control are important tasks [10][11][12][13][14][15]. Such control can be effectively performed by using the luminescent methods.…”