Photoluminescence of gold, copper and niobium as a function of temperature

Abstract

The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Keywords:Photoluminescence, gold, copper, niobium, emission-spectra, purity AbstractA specially constructed instrument for measuring the low intensity photoluminescence emission spectra of metals is described. It uses low luminescence optical components and dedicated sample mounting techniques. Room temperature measurements agree closely with literature spectra for high purity gold and are found to be sensitive to 100 p.p.m. impurities. Detailed spectra are presented, which are weakly temperature dependent, for gold, copper and unpolished niobium between room temperature and 100 K. We conclude that this work provides accurate luminescence data for Au from 300 K down to 100 K. Although the (variable temperature) luminescence data for Cu are consistent both with the room temperature experimental data in the literature and theory, we conclude the role of surface adsorbates and/or oxides cannot be ruled out. Theory suggests that Nb has a factor ~50 lower luminescence intensity than Au and Cu because the real part of the refractive index is a factor ~5 higher and the density of states ~2 eV below the Fermi energy is a factor of ~4 lower than Au and Cu. Measurements are presented for unpolished Nb, but given the lack of signal detection for polished Nb and that theory predicts very weak signals, we conclude that the luminescence signals from pure Nb still remain below the sensitivity of our instrument.

Resonant Raman spectra of diindenoperylene thin films

“…Figure 1(b) presents the preresonant Raman spectra obtained at this wavelength. 29 Below 400 cm −1 , the background becomes even more structured, so that the cross section of the lowest breathing mode at 221 cm −1 could not be analyzed in detail. In this energy region, several broad PL bands from DIP have been observed, but the background in Fig.…”

Synthesis and Characterization of Nano-Particles of Niobium Pentoxide with Orthorhombic Symmetry

“…The PL emission produces information on the lifetime of the excited states, the identification of the surface interface and the impurity levels. It can also provide simultaneous information on intrinsic and extrinsic defects [14,15]. The niobate luminescence has been studied in crystalline materials and is strongly dependent upon the crystal structure [16].…”

Gain and Raman line-broadening with graphene coated diamond-shape nano-antennas

“…This could suggest the existence of a broader line, perhaps due to photoluminescence of our 17 nm thick gold layer. 34 Fig. 5 shows a spatial scan over the graphene coated antenna in 200 nm steps.…”

“…The rectangular patterns were oriented perpendicularly to one another in order to examine the effect of two linearly orthogonal incident polarizations states. The entire metal layout exhibited photoluminescence (PL) when illuminated by the 633 nm HeNe laser [14] and as shown by Figure 2c. The PL signal of gold was small when illuminated with the 785 nm laser and thus, mostly the graphene lines on antennas were accentuated near resonance (Fig.…”