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

Spin-dependent transport properties of Fe3O4/MoS2/Fe3O4 junctions

Magnetite is a half-metal with a high Curie temperature of 858 K, making it a promising candidate for magnetic tunnel junctions (MTJs). Yet, initial efforts to exploit its half metallic nature in Fe3O4/ MgO/Fe3O4 MTJ structures have been far from promising. Finding suitable barrier layer materials, which keep the half metallic nature of Fe3O4 at the interface between Fe3O4 layers and barrier layer, is one of main challenges in this field. Two-dimensional (2D) materials may be good candidates for this purpose. Molybdenum disulfide (MoS2) is a transition metal dichalcogenide (TMD) semiconductor with distinctive electronic, optical, and catalytic properties. Here, we show based on the first principle calculations that Fe3O4 keeps a nearly fully spin polarized electron band at the interface between MoS2 and Fe3O4. We also present the first attempt to fabricate the Fe3O4/MoS2/Fe3O4 MTJs. A clear tunneling magnetoresistance (TMR) signal was observed below 200 K. Thus, our experimental and theoretical studies indicate that MoS2 can be a good barrier material for Fe3O4 based MTJs.Our calculations also indicate that junctions incorporating monolayer or bilayer MoS2 are metallic

Stability and capping of magnetite ultra-thin films

Ultrathin films of Fe3O4 have been grown epitaxially on nearly lattice matched MgO(001). The stability of 4 nm thick films in ambient air and under annealing in an oxygen atmosphere at 200?C has been studied. By magneto optical and Raman measurements we can confirm the presence of the Fe3 O4 phase and the formation of a maghemite top layer passivating the Fe3 O4 thin film. In a second step we are able to demonstrate that this top layer oxidation in ambient air can be prevented by a 2 nm thick magnesium ferrite passivation layer, while a thicker 20 nm MgO layer prevents oxidation even at elevated temperatures

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...