Laser molecular beam epitaxy of ZnO thin films and heterostructures

Abstract

Abstract. We report on the growth of epitaxial ZnO thin films and ZnO based heterostructures on sapphire substrates by laser molecular beam epitaxy (MBE). We first discuss some recent developments in laser-MBE such as flexible ultraviolet laser beam optics, infrared laser heating systems or the use of atomic oxygen and nitrogen sources, and describe the technical realization of our advanced laser-MBE system. Then we describe the optimization of the deposition parameters for ZnO films such as laser fluence and substrate temperature and the use of buffer layers. The detailed structural characterization by x-ray analysis and transmission electron microscopy shows that epitaxial ZnO thin films with high structural quality can be achieved, as demonstrated by a small out-of-plane and in-plane mosaic spread as well as the absence of rotational domains. We also demonstrate the heteroepitaxial growth of ZnO based multilayers as a prerequisite for spin transport experiments and the realization of spintronic devices. As an example, we show that TiN/Co/ZnO/Ni/Au multilayer stacks can be grown on (0001)-oriented sapphire with good structural quality of all layers and well defined inplane epitaxial relations.

Zinc oxide –From dilute magnetic doping to spin transport

“…In the following, we first highlight the recent progress of ZnO thin film technology and device fabrication (). Then, we will review our activities in the fields of injection, transport, and detection of spin‐polarized ensembles of charge carriers in ZnO using an all‐optical , an all‐electrical (), or a combined electrical/optical injection/detection scheme.…”

“…Within the last decade there has been enormous progress in the growth of epitaxial ZnO thin films on Al 2 O 3 substrates by laser‐MBE and other techniques, in spite of the large lattice mismatch of . In the following, we only give a brief overview on the growth issues, details have been published recently ().…”

The influence of growth temperature on structural and optical properties of sputtered ZnO QDs embedded in SiO 2 matrix

“…An essential surface modification needs to be done for each of the desired applications because surface effects radically influence the functionality of semiconductor nanocrystals. For preparing ZnO QDs on SiO 2 thin films a variety of methods have been employed such as pulsed laser deposition (PLD), sol-gel, sputtering, and molecular beam epitaxy (MBE) [9][10][11]. The sputtering technique is the most widely used among the above methods, because of its various advantages, such as a low deposition temperature, preferred orientation and high deposition rate on an amorphous substrate and large deposition area.…”

Fabrication and characterization of p-Si/n-ZnO heterojunction ultraviolet photodetector

“…In the literature, it is found that there exists several techniques, such as molecular beam epitaxy (MBE) [12], metalorganic chemical vapor deposition (MOCVD) [13], atomic layer deposition (ALD) [14], pulsed laser deposition (PLD) [15] and sputtering [16] techniques to be used for growing ZnO thin films. Though, MBE and ALD provides extrimely high precision over the grown layer thickness and its doping profile, their very low growth rate and low throughput restricts their use in batch to batch device fabrication.…”