Bulk In2O3 crystals grown by chemical vapour transport: a combination of XPS and DFT studies

Abstract

A combination of XPS and DFT is used to study the electronic structure and identity of defects in In 2 O 3 crystals grown by a chalcogenides-based Chemical Vapour Transport (CVT) approach. The formation energies of the oxygen and indium vacancies as well as of the indium self-interstitials were calculated employing pseudopotential first principles calculations. Indium self-interstitials were found the most probable point defect in the CVT-In 2 O 3 crystals as derived only theoretically. At the same time both experiment and theory agree on the insignificant (about 0.05 eV) shift of valence bands toward Fermi level caused by the presence of the defects. Our experimental results show that the chalcogenides-based CVT synthesis leads to slightly higher oxygen defectiveness as compared with catalystassisted vapour-solid grown In 2 O 3 micro-rods from pure In and oxygen precursors.

Defect Chemistry and Doping of Ultrawide Band Gap (III)BO3 Compounds

“…Supplemental Figure S10 shows the obtained In 3 d , O 1 s , and B 1 s core level spectra for the InBO 3 thin films. The binding energy for B 1 s is ≈190.52 eV, which is consistent with the previously reported values for B-O bond formation. , Furthermore, in Supplemental Figure S10b, the deconvoluted O 1 s spectrum after annealing indicates the presence of both BO (solid green trace) and InO (solid purple trace) features at 531.5 and 529.3 eV, respectively. , This confirms that we are indeed obtaining the proper bonding structure and not a glass phase, which boron oxide tends to form.…”

“…55,56 Furthermore, in Supplemental Figure S10b, the deconvoluted O 1s spectrum after annealing indicates the presence of both BO (solid green trace) and InO (solid purple trace) features at 531.5 and 529.3 eV, respectively. 57,58 This confirms that we are indeed obtaining the proper bonding structure and not a glass phase, which boron oxide tends to form.…”

3D porous carbon nitride composited oxygen vacancy‐induced indium oxide for high photocatalytic nitrogen fixation on the interfacial surface

“…Therefore, the charge transfer mode between 3DPCN and V O ‐In 2 O 3 follows the Z‐scheme heterojunction mechanism. The electrons at the vacancy level will be trapped, resulting in a longer lifetime of the adsorbed molecular nitrogen, improving the carrier separation in the photocatalytic process 38,39 . On the one hand, the existence of oxygen vacancies enhances the electron transport; on the other hand, it can also enhance the adsorption/activation effect.…”

“…The electrons at the vacancy level will be trapped, resulting in a longer lifetime of the adsorbed molecular nitrogen, improving the carrier separation in the photocatalytic process. 38,39 On the one hand, the existence of oxygen vacancies enhances the electron transport; on the other hand, it can also enhance the adsorption/activation effect. The synergistic effect of the fast electron transport rate and strong adsorption/ activation performance improve the photocatalytic nitrogen fixation efficiency.…”

Theoretical Study of Oxygen-Vacancy Distribution in In2O3

“…For other metal oxides, theoretical investigations showed that the most stable oxygen-vacancy pairs on the ceria (110) surface are located at the next-nearest-neighbor site, and the nearest-neighbored oxygen-vacancy pairs in WO 3 are most stable . In In 2 O 3 , Zatsepin et al reported that the formation energy of a single oxygen vacancy is 3.19 eV, while the formation energies for a pair of oxygen vacancies are 3.47 eV for the most distant oxygen vacancies and 3.51 eV for nearest neighbors, concluding that the clustering of the oxygen vacancies is less energetically favorable than the isolated single defects and the structural stabilities of a pair of oxygen vacancies in the 80 atom supercell are not very distance-dependent.…”