Manuel Alonso-Orts

Universität Bremen | Uni Bremen · Institute of Solid State Physics

Optical microcavities are key elements in many photonic devices, and those based on distributed Bragg reflectors (DBRs) enhance dramatically the end reflectivity, allowing for higher quality factors and finesse values. Besides, they allow for wide wavelength tunability, needed for nano- and microscale light sources to be used as photonic building b...

In this Letter, we report optical confinement in the near-ultraviolet (near-UV) range in Ga2O3 nanowires (NWs) by distributed Bragg reflector (DBR) nanopatterned cavities. High-contrast DBRs, which act as the end mirrors of the cavities of the desired length, are designed and fabricated by focused ion beam etching. The resonant modes of the cavitie...

Remote temperature sensing at the micro- and nanoscale is key in fields such as photonics, electronics, energy, or biomedicine, with optical properties being one of the most used transducing mechanisms for such sensors. Ga2O3 presents very high chemical and thermal stability, as well as high radiation resistance, becoming of great interest to be us...

Tailoring the shape of complex nanostructures requires control of the growth process. In this work, we report on the selective growth of nanostructured tin oxide on gallium oxide nanowires leading to the formation of SnO2/Ga2O3 complex nanostructures. Ga2O3 nanowires decorated with either crossing SnO2 nanowires or SnO2 particles have been obtained...

The influence of self-assembled short-period superlattices (SPSLs) on the structural and optical properties of InGaN/GaN nanowires (NWs) grown by PAMBE on Si (111) was investigated by STEM, EDXS, µ -PL analysis and k·p simulations. STEM analysis on single NWs indicates that in most of the studied nanostructures, SPSLs self-assemble during growth. T...

We report the growth of α-Ga 2 O 3 on -plane α-Al 2 O 3 by conventional plasma-assisted molecular-beam epitaxy (MBE) and In-mediated metal-oxide-catalyzed epitaxy (MOCATAXY). We report a growth-rate-diagram for α-Ga 2 O 3 (101-0), and observe (i) a growth rate increase, (ii) an expanded growth window, and (iii) reduced out-of- lane mosaic spread wh...

We report the growth of α-Ga2O3 on-plane α-Al2O3 by conventional plasma-assisted molecular-beam epitaxy (MBE) and In-mediated metal-oxide-catalyzed epitaxy (MOCATAXY). We report a growth-rate-diagram for α-Ga2O3(10-10), and observe (i) a growth rate increase, (ii) an expanded growth window, and (iii) reduced out-of-lane mosaic spread when MOCATAXY...

The luminescence of In x Ga 1-x N nanowires (NWs) is frequently reported with large red-shifts as compared to the theoretical value expected from the average In-content. Both, compositional fluctuations and radial built-in fields...

Effective doping of semiconductor oxide nanostructures is needed to control n-type conductivity; however, out-diffusion of impurities in high quality crystals is still a bottleneck in nanotechnology. Here, germanium-doped gallium oxide (β-Ga2O3) nanowires have been grown by a thermal evaporation method. Two temperatures, close to Ge melting point,...

β-Ga2O3 intergrowths have been revealed in the SnO2 rutile structure when SnO2/Ga2O3 complex nanostructures are grown by thermal evaporation with a catalyst-free basis method. The structure is formed by a Ga2O3 nanowire trunk, around which a rutile SnO2 particle is formed with [001] aligned to the [010] Ga2O3 trunk axis. Inside the SnO2 particle, β...

High quality Zn‐doped monoclinic gallium oxide micro‐ and nanostructures are obtained by a thermal treatment based on vapor–solid (VS) growth mechanism. Nanowires and ribbons are formed, the latter being the more abundant. The microstructural features are assessed by micro‐Raman and transmission electron microscopy revealing their crystal structure...

In this work, a simple thermal evaporation method has been used to obtain a variety of Ga2O3/SnO2 nano-assemblies with different shape and dimensionality, which may affect their physical properties, especially those influenced by surface properties. The obtained nanostructures have been characterized by electron microscopy related techniques in ord...

Gallium oxide microrods have been grown by an evaporation-deposition method by using a precursor containing lithium in order to check the influence of such dopant on the morphology and physical properties of the obtained β-Ga2O3 structures. SEM studies show that the morphology is modified with respect to undoped gallium oxide, promoting the growth...