ZnMgO‐ZnO quantum wells embedded in ZnO nanopillars: Towards realisation of nano‐LEDs

Abstract

ZnO thin films, ZnMgO/ZnO heterostructures and ZnO nanostructures were fabricated using molecular beam epitaxy (MBE), vapour phase transport (VPT) and an aqueous chemical growth approach (ACG). The possibility to employ several fabrication techniques is of special importance for the realization of unique device structures. MBE was implemented for ZnO-based layer and heterostructure growth. Pronounced RHEED oscillations were used for growth control and optimisation, resulting in high quality ZnO and Zn 1-x Mg x O epilayers and heterostructures, as well as ZnMgO/ZnO quantum wells on sapphire and SiC substrates. A novel advanced VPT approach is developed and sapphire, SiC, ZnO epitaxial layers, and even plastic and glass were implemented as substrates for ZnO growth. The VPT fabrication of ZnO nanopillars, leading to well aligned, c-axis oriented nanopillars with excellent quality and purity is demonstrated. Successful steps were made towards device fabrication on ZnO basis. The nanopillar fabrication technique is combined with MBE technology: MBE-grown ZnMgO/ZnO quantum well structures were grown on ZnO nanopillars presenting significant progress towards nano-LEDs realization.

Investigation of carrier dynamics in Zn1−xMgxO by time-resolved photoluminescence

“…Bandgap engineering for the realization of quantum confinement is achieved by alloying ZnO in ternary compounds, such as (ZnCd)O, (ZnBe)O, and, most prominently, (ZnMg)O. Recently, ZnO/ (ZnMg)O heterostructures have attracted much interest as candidates for UV laser sources [9][10][11][12]. Further applications include light-emitting diodes and photodetectors.…”

Ultraviolet Sensors Based on Two-Dimensional Zinc Oxide Structures

“…In addition, ZnO also been employed as a photodetector in the ultraviolet (UV) region of the electromagnetic spectra [10][11][12] as well as in light emitting diodes (LEDs) [13], UV lasers [14], thin films transparent transistors (TFTs) [15], memory devices [16], and transparent conducting oxides for consumer devices [17]. The subject related to the applications of ZnO was boosted with the advantage of the easy synthesis process compared to the other competitive compounds, such as gallium nitride (GaN) and silicon carbide (SiC).…”

Fabrication of ZnO Nanostructures

“…Bakin et al realized axially oriented QWs on well-aligned NWs by applying MBE. The NWs were grown by a VPT-process on SiC/sapphire templates [12,89]. The QW-related emission was observed at 3.42 eV.…”