Hydrogen shallow donors in ZnO and rutile TiO2

Weber, J.; Lavrov, E. V.; Herklotz, F.

doi:10.1016/j.physb.2011.09.061

Cited by 12 publications

(14 citation statements)

References 40 publications

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“…In Paper VII, it was found that the conductivity of hydrogenated r-TiO 2 is proportional to the concentration of H i , and thus H i is likely to be the main donor in hydrogenated r-TiO 2 . This finding is corroborated by previous studies identifying H i as a shallow donor in r-TiO 2 [237,240,261].…”

Section: Donor Defectssupporting

confidence: 90%

“…Technologically-relevant impurities for doping include, for example, Nb or Li [178,181]. H has been studied extensively in r-TiO 2 [167,231,232,[234][235][236][237][238][239][240], where the incorporation as interstitial defect (H i ) is most favourable [224]. Using fourier-transform infra-red spectroscopy as well as EPR, it was found that the O-H i bond is perpendicular to the c axis (see Fig.…”

Section: Defects In Rutile Titanium Dioxidementioning

confidence: 99%

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Ti- and Fe-related charge transition levels in β−Ga2O3

Zimmermann

Frodason

Barnard

et al. 2020

Applied Physics Letters

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This thesis would not have been possible without the support of many people, and I am eternally grateful for all the support. I hope to see some of you again in the future! The main objective of my PhD project was to study defects in semiconducting oxides within the research project FOXHOUND headed by Prof. Lasse Vines, my main supervisor. I am grateful to Lasse for the opportunity to work on this topic. I have learned much more than I imagined I would when I started. Lasse, you have been a patient and competent supervisor who always took time to answer endless streams of questions. Prof. Truls Norby and Assoc. Prof. Anette Eleonora Gunnaes were co-advisors for my PhD project. I am grateful to Truls for introducing me to the chemist's view on defects and his group FASE/ELCHEM. I am truly sad that I did not get to collaborate more with Anette. I also want to thank Prof. Eduard Monakhov and the late Prof. Bengt Gunnar Svensson. Both were valuable unofficial advisers on my PhD, and helped moving my work along. Most of my work was carried out within the semiconductor physics group at the University of Oslo (LENS), and I would like to thank of all its current and former members for contributing to my work in many ways. There are some people who deserve special thanks. First of all, I am grateful to my long-term office mates Torunn, Sigbjørn and Josef for sharing many conversations and being there for each other. Secondly, I am particularly grateful to all my close collaborators at LENS, and especially Julie, Philip, Ymir, Vegard R., Vegard O., Viktor and Espen. I also want to thank our engineers (Micke, Halvor, Christoph and Viktor) and administrative staff (Marit, Heine and Kristin) for keeping things running! Also, thanks to Ilia, Robert, Vegard R. and Jon for taking care of the needs of the E-Lab and the Online-Setup. I was a co-supervisor for two master students: Vegard R. and Espen. I hope both of them learned something from me, because I did definitely learn from them. I am particularly grateful to Vegard R. for being a large part in building the steady-state photo-capacitance setup used in this work. I also would like to thank all my co-authors from outside of Oslo: Frank from Dresden, Willem, Walter and Danie from Pretoria, Klaus and Zbigniew from Berlin, Antti from Aalto and Joel from California. Special thanks to Willem, Walter and Danie for hosting me in Pretoria and showing me around. Last but not least, I would like to thank my family and my friends for their support!

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Section: Donor Defectssupporting

confidence: 90%

Section: Defects In Rutile Titanium Dioxidementioning

confidence: 99%

Ti- and Fe-related charge transition levels in β−Ga2O3

Zimmermann

Frodason

Barnard

et al. 2020

Applied Physics Letters

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“…The fate of proton in rutile TiO 2 crystal was recently described based on a combined IR spectroscopic and theoretical study. 70 IR photons can stimulate proton transport because the diffusion is highly efficient with low energy barriers and occurs along the large open c channels even at temperature 6 K -40 K. 68,69 The localized O-H bonds are probably aligned perpendicularly to the c-axis of TiO 2 . 70 Due to the coupling of the O-H stretch mode to a waging mode, hydrogen transfer to a neighboring oxygen site is enabled.…”

Section: Discussionmentioning

confidence: 99%

Hydrogen spillover on Rh/TiO₂: the FTIR study of donated electrons, co-adsorbed CO and H/D exchange

Panayotov

Ivanova

Mihaylov

et al. 2015

Phys. Chem. Chem. Phys.

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Hydrogen dissociation and spillover on supported metal nanoparticles have received renewed interest because these chemical processes are closely related to applications in heterogeneous catalysis and hydrogen storage. In heterogeneous catalysis, spillover can control the reaction rate and selectivity of a wide range of reactions, e.g. hydrogenation, synthesis of methanol and hydroisomerization. In this work, we combine three spectroscopic approaches, i.e. the FT-IR spectroscopy of donated electrons, co-adsorbed CO and H/D exchange, to obtain detailed information on the dynamics of hydrogen interaction with a model 1.3% Rh/TiO2 catalyst. Our spectroscopic results helped us to build a physical picture of the processes occurring during the H-spillover on Rh/TiO2. It was found that molecular H2 dissociates on nanocrystalline Rh; H atoms spillover onto the titania thus protonating the semiconductor, while donating electrons to shallow trap (ST) states and the conduction band (CB) of TiO2. These donated electrons are observed by their specific IR features. By simultaneously monitoring the changes in the vibrational modes of CO, and, the infrared absorbance due to transitions involving CB and ST electrons, we found that both CO-reduced and partially re-oxidized Rh nanocrystallites promote the H-spillover and thus the n-doping of TiO2 materials. Upon evacuation, the process reverses: hydrogen atoms spillover back to Rh nanoparticles where they recombine to form H2 molecules that desorb from the surface. These new mechanistic insights into the process of H2 dissociation and spillover on the powder Rh/TiO2 catalyst call for further model surface science studies with model metal nanoparticle-single crystal substrate systems, in which a detailed picture of energetics and spatial distribution of hydrogen and injected electrons could be obtained.

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“…Пред-полагается, что межузельный водород нестабилен при комнатной температуре и отжигается за несколько недель [28], а водород в позиции замещения стабилен до ∼ 500 • С [29,30]. В спектрах низкотемпературной ФЛ мелкому водородному донору, вводимому Н-обработкой, приписывают полосу I 4 [13,31,32] при ∼ 3.363 эВ, ко-торая идентифицирована как водород в кислородной вакансии (H O ) [33]. Водородному донору приписывают также линию при 3.360 эВ, идентифицированную как мелкий донор -водород в BC положении [33].…”

Section: обсуждение результатовunclassified

“…В спектрах низкотемпературной ФЛ мелкому водородному донору, вводимому Н-обработкой, приписывают полосу I 4 [13,31,32] при ∼ 3.363 эВ, ко-торая идентифицирована как водород в кислородной вакансии (H O ) [33]. Водородному донору приписывают также линию при 3.360 эВ, идентифицированную как мелкий донор -водород в BC положении [33]. Можно отметить, что обработка ZnO в водородной плазме часто подавляет узкие пики ФЛ в низкотемпературной по-лосе NBE, взамен появляется широкая бесструктурная полоса, что, по-видимому, связано с разупорядочением поверхности [32,34].…”

Section: обсуждение результатовunclassified

Влияние Термических И Плазменных Обработок На Фотолюминесценцию Пленок Оксида Цинка

Абдуллин¹,

Гриценко²,

Кумеков³

et al. 2018

Физика И Техника Полупроводников

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The structure and electrical properties of ZnO films and the effect of annealing in a hydrogen-plasma atmosphere on the photoluminescence spectra of the films are studied. Short-term plasma treatment in a hydrogen atmosphere improves the electrical properties and brings about the appearance of an intense near-band-edge photoluminescence band. The heavy dependence of the intensity and spectral shape of nearband- edge photoluminescence on the conditions of preliminary annealing is observed. It is shown that the photoluminescence spectrum consists of several contributions. The effect of an ultraviolet-radiation-induced increase in the photoluminescence intensity is observed. The effect is reversible: the photoluminescence signal is intensified after exposure to ultraviolet radiation and reduced to the initial intensity upon keeping the samples in the dark. The nature of experimentally observed metastable shallow donors is discussed.

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Hydrogen shallow donors in ZnO and rutile TiO2

Cited by 12 publications

References 40 publications

Ti- and Fe-related charge transition levels in β−Ga2O3

Ti- and Fe-related charge transition levels in β−Ga2O3

Hydrogen spillover on Rh/TiO₂: the FTIR study of donated electrons, co-adsorbed CO and H/D exchange

Влияние Термических И Плазменных Обработок На Фотолюминесценцию Пленок Оксида Цинка

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Hydrogen shallow donors in ZnO and rutile TiO2

Cited by 12 publications

References 40 publications

Ti- and Fe-related charge transition levels in β−Ga2O3

Ti- and Fe-related charge transition levels in β−Ga2O3

Hydrogen spillover on Rh/TiO2: the FTIR study of donated electrons, co-adsorbed CO and H/D exchange

Влияние Термических И Плазменных Обработок На Фотолюминесценцию Пленок Оксида Цинка

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Hydrogen spillover on Rh/TiO₂: the FTIR study of donated electrons, co-adsorbed CO and H/D exchange