96 citations · 613 across the 24 of their papers we have counts for
24 papers
Enabling two-dimensional electron gas with high room-temperature electron mobility exceeding 100 cm/Vs at a perovskite oxide interface
Georg Hoffmann, Martina Zupancic, Aysha A. Riaz +7
In perovskite oxide heterostructures, bulk functional properties coexist with emergent physical phenomena at epitaxial interfaces. Notably, charge transfer at the interface between…
Etching of elemental layers in oxide molecular beam epitaxy by O2-assisted formation and evaporation of their volatile suboxide: The examples of Ga and Ge
Wenshan Chen, Kingsley Egbo, Huaide Zhang +2
The delivery of an elemental cation flux to the substrate surface in the oxide molecular beam epitaxy (MBE) chamber has been utilized not only for the epitaxial growth of oxide thi…
Phase-selective growth of - vs -GaO and (InGa)O by In-mediated metal exchange catalysis in plasma-assisted molecular beam epitaxy
A. Ardenghi, O. Bierwagen, J. Lähnemann +4
Its piezo- and potentially ferroelectric properties make the metastable kappa polymorph of GaO an interesting material for multiple applications, while In-incorporation int…
In-situ study and modeling of the reaction kinetics during molecular beam epitaxy of GeO2 and its etching by Ge
Wenshan Chen, Kingsley Egbo, Hans Tornatzky +3
Rutile GeO2 has been predicted to be an ultra-wide bandgap semiconductor suitable for future power electronics devices while quartz-like GeO2 shows piezoelectric properties. To exp…
Acceptor and compensating donor doping of single crystalline SnO (001) films grown by molecular beam epitaxy and its perspectives for optoelectronics and gas-sensing
Kingsley Egbo, Jonas Lähnemann, Andreas Falkenstein +2
(La and Ga)-doped tin monoxide (stannous oxide, tin (II) oxide, SnO) thin films were grown by plasma-assisted and suboxide molecular beam epitaxy with dopant concentrations ranging…
Epitaxial synthesis of unintentionally doped p-type SnO (001) via suboxide molecular beam epitaxy
Kingsley Egbo, Esperanza Luna, Jonas Lähnemann +7
By employing a mixed SnO+Sn source, we demonstrate suboxide molecular beam epitaxy growth of phase-pure single crystalline metastable SnO(001) thin films at a growth rate of ~1…
Tackling Disorder in -GaO
Laura E. Ratcliff, Takayoshi Oshima, Felix Nippert +19
GaO and its polymorphs are attracting increasing attention. The rich structural space of polymorphic oxide systems such as GaO offers potential for electronic struc…
Towards controllable Si-doping in oxide molecular beam epitaxy using a solid SiO source: Application to -Ga2O3
A. Ardenghi, O. Bierwagen, A. Falkenstein +4
The oxidation-related issues in controlling Si doping from the Si source material in oxide molecular beam epitaxy (MBE) is addressed by using solid SiO as an alternative source mat…
The electrical conductivity of cubic (InGa)O films (): Native point defects, Sn-doping, and the surface electron accumulation layer
Alexandra Papadogianni, Takahiro Nagata, Oliver Bierwagen
The alloying of the group-III transparent semiconducting sesquioxides InO and GaO can lead to a modulation of the properties of the parent compounds, e.g., the shal…
Drastically enhanced cation incorporation in the epitaxy of oxides due to formation and evaporation of suboxides from elemental sources
Georg Hoffmann, Zongzhe Cheng, Oliver Brandt +1
In the molecular beam epitaxy of oxide films, the cation (Sn, Ga) or dopant (Sn) incorporation does not follow the vapor pressure of the elemental metal sources, but is enhanced by…
Molecular beam epitaxy of single-crystalline bixbyite (InGa)O films (): Structural properties and consequences of compositional inhomogeneity
Alexandra Papadogianni, Charlotte Wouters, Robert Schewski +9
In this work, we show the heteroepitaxial growth of single-crystalline bixbyite (InGa)O films on (111)-oriented yttria-stabilized zirconia substrates using plas…
Bandgap widening and behavior of Raman-active phonon modes of cubic single-crystalline (In,Ga)O alloy films
Johannes Feldl, Martin Feneberg, Alexandra Papadogianni +5
The influence of Ga incorporation into cubic InO on the electronic and vibrational properties is discussed for (In,Ga)O alloy films grown by molecular b…
Adsorption-Controlled Growth of Ga2O3 by Suboxide Molecular-Beam Epitaxy
Patrick Vogt, Felix V. E. Hensling, Kathy Azizie +15
This paper introduces a growth method---suboxide molecular-beam epitaxy (S-MBE)---which enables the growth of Ga2O3 and related materials at growth rates exceeding 1 micrometer per…
Conduction Mechanisms in Epitaxial NiO/Graphene Gas Sensors
Somayeh Saadat Niavol, Melanie Budde, Alexandra Papadogianni +9
Integrated, highly sensitive and reversible sensor devices for toxic and hazardous gases in environmental pollution monitoring can be realized with graphene-based materials. Here w…
Offcut-related step-flow and growth rate enhancement during (100) -Ga2O3 homoepitaxy by metal-exchange catalyzed molecular beam epitaxy (MEXCAT-MBE)
Piero Mazzolini, Andreas Falkenstein, Zbigniew Galazka +2
In this work we investigate the growth of -Ga2O3 homoepitaxial layers on top of (100) oriented substrates via indium-assisted metal exchange catalyzed molecular beam epitaxy (ME…
SnO/-Ga2O3 vertical heterojunction diodes
Melanie Budde, Daniel Splith, Piero Mazzolini +6
Vertical heterojunction diodes were prepared by plasma-assisted molecular beam epitaxy of unintentionally-doped -type SnO layers with hole concentrations ranging from $p=10…
Isotopic study of Raman active phonon modes in -GaO
Benjamin M. Janzen, Piero Mazzolini, Roland Gillen +5
Holding promising applications in power electronics, the wide band gap material gallium oxide has emerged as a vital alternative to materials like GaN and SiC. The detailed study o…
Plasma-assisted molecular beam epitaxy of SnO(001) films: Metastability, hole transport properties, Seebeck coefficient, and effective hole mass
Melanie Budde, Piero Mazzolini, Johannes Feldl +6
Transparent conducting or semiconducting oxides are important materials for (transparent) optoelectronics and power electronics applications. While most of these oxides can be dope…
Influence of Polymorphism on the Electronic Structure of GaO
Jack E. N. Swallow, Christian Vorwerk, Piero Mazzolini +21
The search for new wide band gap materials is intensifying to satisfy the need for more advanced and energy efficient power electronic devices. GaO has emerged as an altern…
Towards smooth (010) beta-Ga2O3 films homoepitaxially grown by plasma assisted molecular beam epitaxy: The impact of substrate offcut and metal-to-oxygen flux ratio
Piero Mazzolini, Oliver Bierwagen
Smooth interfaces and surfaces are beneficial for most (opto)electronic devices based on thin films and their heterostructures. For example, smoother interfaces in (010) beta-Ga2O3…
The two-dimensional electron gas of the In2O3 surface: Enhanced thermopower, electrical transport properties, and its reduction by adsorbates or compensating acceptor doping
Alexandra Papadogianni, Julius Rombach, Theresa Berthold +4
In2O3 is an n-type transparent semiconducting oxide possessing a surface electron accumulation layer (SEAL) like several other relevant semiconductors, such as InAs, InN, SnO2, and…
Structural, optical, and electrical properties of unintentionally doped NiO layers grown on MgO by plasma-assisted molecular beam epitaxy
Melanie Budde, Carsten Tschammer, Philipp Franz +7
NiO layers were grown on MgO(100), MgO(110), and MgO(111) substrates by plasma-assisted molecular beam epitaxy under Ni-flux limited growth conditions. Single crystalline growth wi…
Plasma-assisted molecular beam epitaxy of NiO on GaN(00.1)
Melanie Budde, Thilo Remmele, Carsten Tschammer +8
The growth of NiO on GaN(00.1) substrates by plasma-assisted molecular beam epitaxy under oxygen rich conditions was investigated at growth temperatures between 100 C and…
The electrical conductivity tensor of -Ga2O3 analyzed by van der Pauw measurements: Inherent anisotropy, off-diagonal element, and the impact of grain boundaries
Christian Golz, Vanesa Hortelano, Fariba Hatami +3
The semiconducting oxide -Gallium Oxide (-GaO) possesses a monoclinic unit cell whose low symmetry generally leads to anisotropic physical properties. For example…