Kinetic Study of the Thermal Quenching of the Ultraviolet Emission in Zn2GeO4 Microrods

• Published in: Physica status solidi. PSS-RRL. Rapid research letters 2022-06, Vol.16 (6), p.n/a
• Main Authors: Dolado, Jaime, Hidalgo, Pedro, Méndez, Bianchi
• Format: Article
• Language: English
• Subjects: Decay rate; Emission analysis; Low temperature; Luminescence; microrods; Mixtures; Optical properties; Photoluminescence; Quenching; Room temperature; temperature dependence luminescence; thermal quenching; Ultraviolet emission; zinc germanate; Zinc oxide
• ISSN: 1862-6254; 1862-6270
• DOI: 10.1002/pssr.202100613

Zn2GeO4 microrods obtained by thermal evaporation of a compacted powder mixture of ZnO and Ge exhibit quite intense UV luminescence at low temperatures. Herein, the luminescence properties of Zn2GeO4 microrods are studied for 2:1 and 1:1 ZnO:Ge ratio in the precursor mixture. In both cases, Zn2GeO4 microrods of high crystal quality produce a 355 nm emission under aforementioned bandgap excitation conditions at low temperatures. However, this emission vanishes at room temperature (RT) in the 1:1 samples while it is kept in the 2:1 ones. Herein this work, the thermal quenching of the UV luminescence is studied by means of steady and time‐resolved photoluminescence techniques from 4 K up to RT for both Zn2GeO4 microrods. The analysis of the results leads us to conclude that although the luminescence mechanisms are the same in both cases, a higher decay rate is observed in the 1:1 in both intensity and lifetime, which explain the observed thermal quenching at RT. The luminescence of Zn2GeO4 microrods obtained by thermal evaporation using a different ZnO:Ge ratio (1:1 and 2:1) is studied. The UV emission vanishes at room temperature (RT) in the 1:1 sample, while survives in the 2:1 one up to RT. Temperature‐dependent photoluminescence (PL) measurements show an abrupt PL quenching and allow assessment of the non‐radiative channel in both samples.