Studies of electrical and crystal properties of ALD grown ZnO

Aluminium doped ZnO (AZO) is an interesting low cost transparent conducting oxide with further use as inorganic transport layer in multilayer solar cells as well as sensors. Here we present our work on atomic layer deposited (ALD) thin films where with optimized growth conditions we can maintain resistivity below 10-3 Ωcm even in 50-65 nm thin films grown at low temperatures (530 K) We discuss the influence of crystallographic texture for ALD grown films by comparing plain glass, Al2O3 c-plane, and Al2O3 a-plane substrates

Structure and morphology of spinel MgFe2O4 nanoparticles for water purification

In this work, spinel magnesium ferrite MgFe2O4 nanoparticles were synthesized by convential sol-gel methods. The study was focused on obtaining nanoparticles with the maximum content of specified ferrites, nanosized and uniform particles, with high crystallinity for water purification application...

Growth of ZnO:Al by atomic layer deposition: deconvoluting the contribution of hydrogen interstitials and crystallographic texture on the conductivity

© 2019 Elsevier B.V. Aluminium doped ZnO (AZO) is an interesting low cost transparent conducting oxide with further use as an inorganic transport layer in multilayer solar cells. Here we present our work on atomic layer deposited (ALD) thin films where, with optimised growth conditions, we can obtain resistivities of 1 × 10−3 Ωcm even in 50–80 nm thin films grown at low temperatures (250 °C). We discuss the influence of crystallographic texture for ALD grown films by comparing plain glass, c-plane Al2O3, and a-plane Al2O3 substrates. We show that the doping mechanism in ALD grown AZO is more complex than for e.g. sputtered material as a substantial hydrogen interstitial related background doping occurs. We compare results from as grown samples with those briefly annealed at 320 °C in nitrogen. This process leads to an increased Hall mobility due to improved grain boundary passivation, but reduced carrier concentration due to partial loss of hydrogen interstitials

SUPERHYDROPHOBIC SIO2/TRIMETHYLCHLOROSILANE COATING FOR SELF-CLEANING APPLICATION OF CONSTRUCTION MATERIALS

This study has demonstrated, for the first time, the potential application of coatings to protect bricks or architectures against detrimental atmospheric effects via a self-cleaning approach. In this research, a facile fabrication method was developed to produce amorphous SiO2 particles and their hierarchical structures via applying trimethylchlorosilane (TMCS). They were fully characterized by various surface analytic tools, including a goniometer, SEM, AFM, zeta sizer, and a spectroscopic technique (FTIR), and then applied as super hydrophobic coatings on glass and sand. The characterization results revealed that the SiO2 particles are amorphous, quasi-spherical particles with an average diameter of 250–300 nm, and the hierarchical structures in the film were assembled from building blocks of SiO2 and TMCS. The wettability of the films can be controlled by changing the pH of the SiO2/TCMS dispersion. A super hydrophobic surface with a water contact angle of 165° ± 1° was achieved at the isoelectric point of the films. The obtained translucent super hydrophobic SiO2/TMCS coatings show good self-cleaning performances for glass and sand as construction materials. This study indicated that the superhydrophobic coatings may have potential applications in the protection of buildings and construction architectures in the future

Step bunching with both directions of the current: Vicinal W(110) surfaces versus atomistic scale model

We report for the first time the observation of bunching of monoatomic steps on vicinal W(110) surfaces induced by step up or step down currents across the steps. Measurements reveal that the size scaling exponent {\gamma}, connecting the maximal slope of a bunch with its height, differs depending on the current direction. We provide a numerical perspective by using an atomistic scale model with a conserved surface flux to mimic experimental conditions, and also for the first time show that there is an interval of parameters in which the vicinal surface is unstable against step bunching for both directions of the adatom drift.Comment: 17 pages, 10 figure

Electromigration of atoms on vicinal surfaces at high temperatures

THESIS 1095

Magnetic and electronic properties of PtSe2 thin film

Two-dimensional (2D) materials with single or few atomic layers have attracted significant attention from the scientific community due to their potential transport physics and prospects for technological applications. A variety of 2D materials beyond graphene with different bandgaps have been synthesized in recent years. One of them is platinum diselenide (PtSe2) with the bandgap energy of 1.2 eV at one monolayer. However, the low throughput synthesis of high quality 2D thin films has thus far hindered the development of devices. The methods of molecular beam epitaxy (MBE) and chemical vapor deposition (CVD) have been used to achieve large-scale fabrication of PtSe2 films, which were fabricated from Pt thin films with different thickness through selenization process. We have grown Fe3O4 on MgO substrate by MBE system in order to fabricate even better epitaxial Pt thin films. After the fabrication of PtSe2 on Fe3O4/MgO, the electronic and magnetic properties of the interface between two epitaxial grown thin films of platinum diselenide and magnetite have been studied

Studies of electrical and crystal properties of ALD grown ZnO

Aluminium doped ZnO (AZO) is an interesting low cost transparent conducting oxide with further use as inorganic transport layer in multilayer solar cells as well as sensors. Here we present our work on atomic layer deposited (ALD) thin films where with optimized growth conditions we can maintain resistivity below 10-3 Ωcm even in 50-65 nm thin films grown at low temperatures (530 K) We discuss the influence of crystallographic texture for ALD grown films by comparing plain glass, Al2O3 c-plane, and Al2O3 a-plane substrates

Structure and morphology of spinel MgFe2O4 nanoparticles for water purification

In this work, spinel magnesium ferrite MgFe2O4 nanoparticles were synthesized by convential sol-gel methods. The study was focused on obtaining nanoparticles with the maximum content of specified ferrites, nanosized and uniform particles, with high crystallinity for water purification application...