High‐Throughput Electrical Potential Depth‐Profiling in Air

Abstract

The operation of thin-film electronic devices is dictated by the band alignment at the interfaces of the various layers. While a number of methods for measuring the depth profile of the electrical potential at interfaces have emerged, these are typically arduous to perform and involve the use of ultra-high vacuum, complicated sample preparation and/or suffer from poor resolution. Here we present a method to directly map the depth profile of the electrical potential at an interface in air by growing a sample with an intentional thickness gradient and correlating the surface potential, measured using (macroscale) scanning Kelvin probe, to the thickness at each point. Our approach is non-destructive and rapid, is ideal for large substrates and films grown with an inherent thickness gradient. It enjoys very high depth (2 nm) and energy resolution (5 meV), comparable to other methods. In this work we develop and demonstrate the method on layer.

Universal Work Function of Metal Oxides Exposed to Air

“…While the results presented here constitute the most comprehensive and systematic study performed in air, similar reductions in the work functions of oxides have previously been observed upon exposure to air (NiO, MoO 3 , WO 3 , Co 3 O 4 , V 2 O 5 , SnO 2 , and ITO). In a recent review, Chen et al highlight that the work functions of “high work function oxides” are 0.5–1.6 eV greater for films grown and characterized in vacuum than their air‐exposed or solution‐processed counterparts.…”

“…The work function and the ionization energy of the oxide surfaces were measured in the dark, under ambient conditions at 22 ± 3 °C with a relative humidity of ≈40 ± 10%, using a scanning Kelvin probe combined with an air photoemission system (ASKP150200, KP Technology Ltd.). The 2 mm diameter stainless steel tip was frequently calibrated against a gold reference that was calibrated using air photoemission with an accuracy of 50 meV . The accuracy of relative work functions was 3 meV …”

“…The 2 mm diameter stainless steel tip was frequently calibrated against a gold reference that was calibrated using air photoemission with an accuracy of 50 meV . The accuracy of relative work functions was 3 meV …”

Vertically aligned Co3O4 nanorods as a platform for inverted all‐oxide heterojunctions

“…The structure delivers enhanced carrier separation due to promoted light re‐absorption (yellow arrows represent internal light scattering in the NRs heterojunction structure). (inset) The electronic band structure for the junction is reported, based on data from the literature accounting for the vacuum level of the three oxide materials (FTO, Co 3 O 4 , TiO 2 ) based on refs, [ 37,38 ] and the energy gaps calculated from the Tauc plots…”

Работа Выхода Электрона Углеродных Нанокомпозитных Пленок По Данным Вакуумной И Атмосферной Фотоэмиссии

“…Методом рентгеновской фотоэлектронной спектроскопии (РФЭС) наряду с s p 2и s p 3 -связями в образцах было обнаружено наличие углеродной связи c s p 1 -гибридизацией [7], поэтому пленки были классифицированы как карбинсодержащие. Методом комбинационного рассеяния [8] Во время измерений спектров фотоэмиссии (APS) [9,10] образцы с пленками ЛЦУ устанавливались на круглой алюминиевой пластине с возможностью перемещения в трех направлениях. Зонд, имеющий наконечник из золотого сплава диаметром 2 mm, располагался вертикально над образцом.…”