Effect of growth conditions on surface morphology and photoelectric work function characteristics of iridium oxide thin films

Abstract

Stability and chemical composition of thermally grown iridium-oxide thin filmsThe effect of thermal growth conditions on the morphology and surface work function of iridium oxide thin films grown by annealing Ir thin films in an O 2 ambient is presented. The samples were analyzed using x-ray diffraction, x-ray photoelectron spectroscopy, atomic force microscopy, and photoelectric work function measurements. It is found that, with increasing temperature, IrO 2 changes from ͑110͒ oriented to a mixture of ͑110͒ and ͑200͒ during the oxide growth. This is manifested as a sharpening of the photoelectric energy distributions at 800°C. The surface work function was determined to be 4.23 eV using ultraviolet photoelectron spectroscopy. X-ray photoelectron spectroscopy analysis shows that IrO 2 starts to form at 600°C accompanied by surface roughening. Annealing the Ir film at 900°C in O 2 ambient leads to almost complete desorption of the film.

All-oxide spin Seebeck effects

“…Importantly, IrO 2 is an n-type transparent semiconductor of which its work function is very close to metals, such as Ag [27], making it easier to form an Ohmic contact between IrO 2 and metallic electrodes [26]. This situation is indispensable for detecting the ISHE in IrO 2 if the output voltage is in the order of submicrovolts or less.…”

Response to “Comment on ‘Thermally stable Ir Schottky contact on AlGaN/GaN heterostructure’ ” [Appl. Phys. Lett 83, 1272 (2003)]

“…In deriving the earlier conclusion, it was assumed that the work function of IrO 2 is 1.0 eV lower than that of Ir. 3,4 However, it is unclear that the work function of IrO 2 is lower than that of Ir and the increase of Al composition near the Ir/AlGaN interface by the oxidation annealing.…”

“…The work function of IrO 2 was measured to be 4.23 eV using ultraviolet photoelectron spectroscopy measurement 3 when Ir film on LaAlO 3 substrate was annealed to form IrO 2 . Lin 2 assumed that the work function of Ir is about 1.0 eV higher than that of IrO 2 by observing the field emission characteristics of IrO 2 tips.…”

Modulating charge density and inelastic optical response in graphene by atmospheric pressure localized intercalation through wrinkles

“…17 The presence of type A-regions is interpreted in this light: in the absence of a protecting layer hindering surface air oxidation, an Ir oxide rapidly forms. 18,19 This oxide has a low conductivity, compared to the rest of the sample (SI, Figure S3). Type B-regions, which are covered with graphene, are tentatively identified at this point as Ir oxide ultrathin films progressively forming upon the reactive intercalation of oxygen.…”