The dynamics of ultraviolet-induced oxygen vacancy at the surface of insulating SrTiO 3 (0 0 1)

Abstract

A c c e p t e d M a n u s c r i p t Highlights (for review) -The dynamics of UV-induced oxygen vacancy is studied from the change of surface resistance.-The formation of 2DEG at the insulating surface of SrTiO 3 is confirmed by ARPES.-The UV-induced change in resistance responds differently to oxygen/gas exposure.-The behavior of resistance recovery suggests an alternative method of low-pressure sensing.Page 2 of 5 A c c e p t e d M a n u s c r i p t The effect of ultra-violet (UV) irradiation on the electronic structure and the surface resistance of an insulating SrTiO3(001) crystal is studied in this work. Upon UV irradiation, we shows that the two-dimensional electron gas (2DEG) emerges at the insulating SrTiO3 surface and there is a pronounced change in the surface resistance. By combining the observations of the change in valance band and the resistance change under different environments of gas pressure and gas species, we find that UV-induced oxygen vacancies at the surface plays a major role in the resistance change. The dynamic of the resistance change at different oxygen pressures also suggests an alternative method of low-pressure sensing.

Evidence for indirect band gap in BaSnO3 using angle-resolved photoemission spectroscopy

“…The state  spreads over wide momentum space without clear dispersion, so that it's hard to consider the states as the valence band but as the localized in-gap states. Such in-gap states are found in other semiconducting oxides, but at different energyeis from that of the BSO, e.g., that for ATiO 3 (A=Sr, Ba) and In 2 O 3 is 0.6-1.1 eV and ~1.6 eV below CBM, respectively [39,42,43]. However, there are striking differences between the ATiO 3 and In 2 O 3 with respece to the contribution of free electrons from a single O vacancy.…”

Interplay of negative electronic compressibility and capacitance enhancement in lightly-doped metal oxide Bi0.95La0.05FeO3 by quantum capacitance model

“…1(b,f)) which could be described by the photogeneration of charge carriers. However, since the capacitance measured here does not instantly recover back to its original value when the irradiation is off, such changes are attributed to the creation of a thin conductive layer upon the insulating bulk referred to as a quantum-confined electron gas which is related to the creation of oxygen vacancies induced by light irradiation 26,31,32 .…”

Spectral weight reduction of two-dimensional electron gases at oxide surfaces across the ferroelectric transition

“…From our previous study, by using angle-resolved photoemission spectroscopy(ARPES), we showed that a similar 2DEG can be formed on the bare surface under exposure to intense ultraviolet irradiation 14 . The carrier densities were up to the same order as in the interfacial systems, and could be controlled by the UV irradiation dose which induces oxygen vacancies at the surface 15 – 17 . The corresponding changes of these carrier densities could also be observed from the surface resistivity 17 .…”