Surface Structure and Electronic Properties of Lu3Al5O12

Abstract

Lu3Al5O12 (LuAG) is a famous scintillator that has the advantages of high efficiency, high light yield, and fast decay after being doped with active ions. F centers (oxygen vacancies with two electrons) and antisite defects are the most important defects and can greatly affect the scintillation performance in the bulk materials. However, the surface defects that strongly affect the spectrum of a single crystal (SC) and single crystal film (SCF) and the effect on the electronic properties have not been investigated. In this context, we investigate the surface structural and electronic properties of Lu3Al5O12 using first-principles calculations. The Lu atoms are six-fold and seven-fold coordinated with the O atoms on the S1 and S2 surfaces. The surface oxygen vacancies and antisites have considerably lower formation energies than for the bulk. The oxygen vacancies in the bulk introduce the occupied states in the band gap. The surface electronic states are mainly located on the oxygen atoms and can be eliminated via oxygen vacancies.

Influence of Carbon Doping on Stability of Intrinsic Defects in Y3Al5O12 and Lu3Al5O12

“…[9] The lattice constant was calculated to be 11.87 Å, which agreed well with the experimental value of 11.91 Å. [10] By the analogy to the study YAG:C, [5] 21 types of possible isolated and complex defects were considered (Table 1). We did not consider carbon-or aluminum-occupying Lu sites, as well as Lu vacancies, because, according to the element analysis of YAG crystals grown under CO-containing atmosphere, crystal surface was severely depleted with aluminum and oxygen.…”

Towards deliberate design of persistent phosphors: a study of La–Ga admixing in LuAG:Ce crystals to engineer elemental homogeneity and carrier trap depths

“…Each crystal shows an opaque and rough surface caused by thermal etching and the formation of surface defects. 30,38 Large surface deformation of the crystal was found for large La concentration. The tail of LuAGG:Ce0.075%,La (La = 0.150 and 0.300%) crystals narrows to a conical shape.…”

“…This enhances the segregation behavior in the crystal. Due to the formation of surface defects and thermal etching, 30,38 the crystal rim has a higher affinity for mismatched elements. This imposes a chemical inhomogeneity and the formation of multiple misaligned grains, which would explain the opacity of the rim area of the crystals.…”

Mechanical and thermal properties for corrosion products of lutetium silicates against CMAS

“…23 In theoretical calculations, the surface oxygen vacancies and antisite defects in Lu 3 Al 5 O 12 have been investigated. 24 The electronic structure and mechanical properties of MgAl 2 O 4 and Ca 2 MgSi 2 O 7 are reported in previous theoretical works. [25][26][27] However, the reported results still cannot give a comprehensive understanding of these products.…”