Understanding the UV luminescence of zinc germanate: The role of native defects. (1st September 2020)

• Record Type: Journal Article
• Authors: Dolado, Jaime; Martínez-Casado, Ruth; Hidalgo, Pedro; Gutierrez, Rafael; Dianat, Arezoo; Cuniberti, Gianaurelio; Domínguez-Adame, Francisco; Díaz, Elena; Méndez, Bianchi
• Is Part Of: Acta materialia. Volume 196(2020)
• Page Start: 626
• Page End: 634
• Publication Date: 2020-09-01
• Subjects: Ultraviolet emission -- Photoluminescence -- Native defects -- Zinc germanate -- Density functional theory; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2020.07.009
• Languages: English
• ISSNs: 1359-6454

Abstract

Graphical abstract: Abstract: Achieving efficient and stable ultraviolet emission is a challenging goal in optoelectronic devices. Herein, we investigate the UV luminescence of zinc germanate Zn2 GeO4 microwires by means of photoluminescence measurements as a function of temperature and excitation conditions. The emitted UV light is composed of two bands (a broad one and a narrow one) associated with the native defects structure. In addition, with the aid of density functional theory (DFT) calculations, the energy positions of the electronic levels related to native defects in Zn2 GeO4 have been calculated. In particular, our results support that zinc interstitials are the responsible for the narrow UV band, which is, in turn, split into two components with different temperature dependence behaviour. The origin of the two components is explained on the basis of the particular location of Zn i in the lattice and agrees with DFT calculations. Furthermore, a kinetic luminescence model is proposed to ascertain the temperature evolution of this UV emission. These results pave the way to exploit defect engineering in achieving functional optoelectronic devices to operate in the UV region.