Spatially Resolved Dynamics of Cobalt Color Centers in ZnO Nanowires

Abstract

The dynamics of color centers, being a promising quantum technology, is strongly dependent on the local environment. A synergistic approach of X-ray fluorescence analysis and X-ray excited optical luminescence (XEOL) using a hard X-ray nanoprobe is applied. The simultaneous acquisition provides insights into compositional and functional variations at the nanoscale demonstrating the extraordinary capabilities of these combined techniques. The findings on cobalt doped zinc oxide nanowires show an anticorrelation between the band edge emission of the zinc oxide host and the intra-3d cobalt luminescence, indicating two competing recombination paths. Moreover, time-resolved XEOL measurements reveal two exponential decays of the cobalt luminescence. The fast and newly observed one can be attributed to a recombination cascade within the cobalt atom, resulting from direct excitation. Thus, this opens a new fast timescale for potential devices based on cobalt color centers in ZnO nanowires in photonic circuits.

Unraveling the synergistic effects of Cu-Ag tandem catalysts during electrochemical CO2 reduction using nanofocused X-ray probes

“…8 for further details). A previously established nano-XRF technique 20 , 21 was used for the mapping of the NPs. As depicted in Supplementary Fig.…”

The Enigma of Methanol Synthesis by Cu/ZnO/Al2O3-Based Catalysts

“…Most XEOL experiments on zinc oxide − have been conducted at the Zn L-edges and O K-edges, which exist in the sub 1 keV range, which makes operando study at pressures much above 1 bar, difficult, but not impossible. Equally however, XEOL can also be conducted at the, from an operando perspective, more convenient, K-edge (9.6 keV). Furthermore, the standard temperatures of operation of the methanol synthesis process are not so high that interference from the blackbody radiation of the sample itself might become problematic.…”

Integration of Multijunction Absorbers and Catalysts for Efficient Solar‐Driven Artificial Leaf Structures: A Physical and Materials Science Perspective

“…[258,267,268] In its application, the extraction of meaningful parameters involves different key ingredients: a suitable absorber structure such as a semiconductor double heterostructure, a state-of-the-art measurement setup, a kinetic model appropriate for the description of the sample behavior, and a general analysis method to extract the model parameters of interest from the measured TRPL transients. [258] Specifically, the lifetime of minority charge carriers has already been studied in various semiconductor structures using TRPL, such as in MQW top absorbers and semiconductor nanowires, [269][270][271] or to determine recombination rates and charge extraction processes in perovskite absorbers. [157] TRPL measurements based on time-correlated single-photon counting and its analysis have been advanced, [258] allowing for quantification of charge carrier-trapping kinetics at defect states.…”