scholarly journals Application of Pulsed Laser Deposition in the Preparation of a Promising MoSx/WSe2/C(В) Photocathode for Photo-Assisted Electrochemical Hydrogen Evolution

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1461
Author(s):  
Roman Romanov ◽  
Vyacheslav Fominski ◽  
Maxim Demin ◽  
Dmitry Fominski ◽  
Oxana Rubinkovskaya ◽  
...  
Keyword(s):  
Pulsed Laser Deposition ◽  
Hydrogen Evolution ◽  
Substrate Surface ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Mutual Arrangement ◽  
Energy Bands ◽  
Laser Plume ◽  
Solar Water Splitting ◽  
Catalytically Active

We studied the possibility of using pulsed laser deposition (PLD) for the formation of a MoSx/WSe2 heterostructure on a dielectric substrate. The heterostructure can be employed for effective solar water splitting to produce hydrogen. The sapphire substrate with the conducting C(B) film (rear contact) helped increase the formation temperature of the WSe2 film to obtain the film consisting of 2H-WSe2 near-perfect nanocrystals. The WSe2 film was obtained by off-axis PLD in Ar gas. The laser plume from a WSe2 target was directed along the substrate surface. The preferential scattering of selenium on Ar molecules contributed to the effective saturation of the WSe2 film with chalcogen. Nano-structural WSe2 film were coated by reactive PLD with a nanofilm of catalytically active amorphous MoSx~4. It was established that the mutual arrangement of energy bands in the WSe2 and MoSx~4 films facilitated the separation of electrons and holes at the interface and electrons moved to the catalytically active MoSx~4. The current density during light-assisted hydrogen evolution was above ~3 mA/cm2 (at zero potential), whilst the onset potential reached 400 mV under irradiation with an intensity of 100 mW/cm2 in an acidic solution. Factors that may affect the HER performance of MoSx~4/WSe2/C(В) structure are discussed.

scholarly journals Comparative Study of the Structure, Composition, and Electrocatalytic Performance of Hydrogen Evolution in MoSx~2+δ/Mo and MoSx~3+δ Films Obtained by Pulsed Laser Deposition

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 201 ◽  
Author(s):  
V. Fominski ◽  
M. Demin ◽  
D. Fominski ◽  
R. Romanov ◽  
A. Goikhman ◽  
...  
Keyword(s):  
Pulsed Laser Deposition ◽  
Hydrogen Evolution ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Morphological Properties ◽  
Electrochemical Characteristics ◽  
Laser Plume ◽  
Standard Configuration ◽  
Hydrogen Evolution Reactions ◽  
Ar Gas

Systematic and in-depth studies of the structure, composition, and efficiency of hydrogen evolution reactions (HERs) in MoSx films, obtained by means of on- and off-axis pulsed laser deposition (PLD) from a MoS2 target, have been performed. The use of on-axis PLD (a standard configuration of PLD) in a buffer of Ar gas, with an optimal pressure, has allowed for the formation of porous hybrid films that consist of Mo particles which support a thin MoSx~2+δ (δ of ~0.7) film. The HER performance of MoSx~2+δ/Mo films increases with increased loading and reaches the highest value at a loading of ~240 μg/cm2. For off-axis PLD, the substrate was located along the axis of expansion of the laser plume and the film was formed via the deposition of the atomic component of the plume, which was scattered in Ar molecules. This made it possible to obtain homogeneous MoSx~3+δ (δ~0.8–1.1) films. The HER performances of these films reached saturation at a loading value of ~163 μg/cm2. The MoSx~3+δ films possessed higher catalytic activities in terms of the turnover frequency of their HERs. However, to achieve the current density of 10 mA/cm2, the lowest over voltages were −162 mV and −150 mV for the films obtained by off- and on-axis PLD, respectively. Measurements of electrochemical characteristics indicated that the differences in the achievable HER performances of these films could be caused by their unique morphological properties.

Microwave Properties of Strontium Barium Niobate Thin Films Grown by Pulsed Laser Deposition

2001 ◽  
Vol 688 ◽  
Author(s):  
Víctor Rodríguez-Santiago ◽  
Yelitza González ◽  
Félix E. Fernández ◽  
Carl H. Mueller ◽  
Fred W. Van Keuls ◽  
...  
Keyword(s):  
Thin Films ◽  
Dielectric Properties ◽  
Pulsed Laser Deposition ◽  
Substrate Surface ◽  
Pulsed Laser ◽  
Phase Shifters ◽  
Laser Deposition ◽  
Strontium Barium Niobate ◽  
Strontium Barium ◽  
High Frequencies

AbstractStrontium barium niobate (SrxBa1−xNb2O6 - SBN) with 0.25≤x≤0.75 is a ferroelectric material of interest for diverse optoelectronic applications. Dielectric properties of bulk SBN crystals were comprehensively studied over 30 years ago for a range of compositions and at frequencies up to 30 MHz, but there is little information on properties at higher frequencies. In particular, and up to the best of our knowledge, there are no published results about SBN thin film dielectric properties at high frequencies. For the study reported here, SBN thin films with x = 0.61 were grown on MgO and LaAlO3 substrates by Pulsed Laser Deposition (PLD). Films with good crystallinity and oriented with c-axis normal to the substrate surface were obtained on both types of substrates, while films on MgO had much better texture due to better lattice matching. Interdigital electrode (IDE) capacitors and coupled microstrip phase shifters (CMPS) were fabricated with both types of samples in order to study dielectric response. Capacitance of the IDE capacitors was measured at 1 MHz as a function of temperature and bias voltage, revealing very low losses but poor capacitance tunability, particularly for samples on MgO. Response of the CMPS structures was measured at room temperature and at high frequencies, up to 21 GHz. Insertion losses were measured up to 28 GHz.

Modeling of Film Growth in Pulsed Laser Deposition

1995 ◽  
Vol 397 ◽  
Author(s):  
M. Tyunin
Keyword(s):  
Growth Rate ◽  
Pulsed Laser Deposition ◽  
Laser Fluence ◽  
Film Growth ◽  
Surface Film ◽  
Substrate Surface ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Ambient Gas ◽  
Deposited Films

ABSTRACTFilm growth in pulsed laser deposition (PLD) is described as a process of sorption of ablated species on the substrate surface. Film growth rate and composition are qualitatively analyzed as a function of laser fluence and ambient gas pressure. As an example, analysis of the film composition is carried out for BiSrCaCuO and PbZrTiO pulsed laser deposited films.

Stability and Structural Characterization of Epitaxial NdNiO3 Films Grown by Pulsed Laser Deposition

2000 ◽  
Vol 658 ◽  
Author(s):  
Trong-Duc Doan ◽  
Cobey Abramowski ◽  
Paul A. Salvador
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Substrate Surface ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Monoclinic Distortion

ABSTRACTThin films of NdNiO3 were grown using pulsed laser deposition on single crystal substrates of [100]-oriented LaAlO3 and SrTiO3. X-ray diffraction and reflectivity, scanning electron microscopy, and atomic force microscopy were used to characterize the chemical, morphological and structural traits of the thin films. Single-phase epitaxial films are grown on LaAlO3 and SrTiO3 at 625°C in an oxygen pressure of 200 mTorr. At higher temperatures, the films partially decompose to Nd2NiO4 and NiO. The films are epitaxial with the (101) planes (orthorhombic Pnma notation) parallel to the substrate surface. Four in-plane orientational variants exist that correspond to the four 90° degenerate orientations of the film's [010] with respect to the in-plane substrate directions. Films are observed to be strained in accordance with the structural mismatch to the underlying substrate, and this leads, in the thinnest films on LaAlO3, to an apparent monoclinic distortion to the unit cell.

scholarly journals Polarity Control of ZnO Films Grown on Ferroelectric (0001) LiNbO3 Substrates without Buffer Layers by Pulsed-Laser Deposition

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 380
Author(s):  
Im Taek Yoon ◽  
Juwon Lee ◽  
Ngoc Cuong Tran ◽  
Woochul Yang
Keyword(s):  
Pulsed Laser Deposition ◽  
Chemical Etching ◽  
Substrate Surface ◽  
Pulsed Laser ◽  
Piezoresponse Force Microscopy ◽  
Interfacial Structure ◽  
Buffer Layers ◽  
Laser Deposition ◽  
Zno Films ◽  
Polarity Determination

For this study, polarity-controlled ZnO films were grown on lithium niobate (LiNbO3) substrates without buffer layers using the pulsed-laser deposition technique. The interfacial structure between the ZnO films and the LiNbO3 was inspected using high-resolution transmission electron microscopy (HR-TEM) measurements, and X-ray diffraction (XRD) measurements were performed to support these HR-TEM results. The polarity determination of the ZnO films was investigated using piezoresponse force microscopy (PFM) and a chemical-etching analysis. It was verified from the PFM and chemical-etching analyses that the ZnO film grown on the (+z) LiNbO3 was Zn-polar ZnO, while the O-polar ZnO occurred on the (-z) LiNbO3. Further, a possible mechanism of the interfacial atomic configuration between the ZnO on the (+z) LiNbO3 and that on the (-z) LiNbO3 was suggested. It appears that the electrostatic stability at the substrate surface determines the initial nucleation of the ZnO films, leading to the different polarities in the ZnO systems.

Growth of Cubic AlN Films on Sapphire(0001) with Atomic Scale Surface Smoothness by Pulsed Laser Deposition

2010 ◽  
Vol 638-642 ◽  
pp. 2921-2926 ◽  
Author(s):  
Tomohiro Yoshitake ◽  
Tsuyoshi Yoshitake ◽  
Kazushi Sumitani ◽  
Ryota Ohtani ◽  
You Nakagawa ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Pulsed Laser Deposition ◽  
Film Growth ◽  
Substrate Surface ◽  
Pulsed Laser ◽  
Growth Conditions ◽  
Atomic Scale ◽  
Laser Deposition ◽  
Normal Surface ◽  
Scale Surface

We have previously reported that -AlN crystallites with diameters of 0.5–1 µm were occasionally grown on sapphire(0001) by pulsed laser deposition, which implied that the migration mobility of the species deposited on the substrate surface might be an insufficient for the film growth of -AlN. In the present study, in order to enhance the crystal growth of -AlN, sapphire(0001) substrates with an atomically smoothness (step-sapphire) were employed. The growth conditions of - and -AlN extended to higher nitrogen-pressures, as compared to those using normal surface sapphire(0001) substrates (normal-sapphire). This is due to the enhancement in the mobility of the deposited species on the substrate surface.

Pulsed laser deposition of nanocomposite MoSex/Mo thin-film catalysts for hydrogen evolution reaction

2015 ◽  
Vol 592 ◽  
pp. 175-181 ◽  
Author(s):  
S.N. Grigoriev ◽  
V.Yu. Fominski ◽  
R.I. Romanov ◽  
M.A. Volosova ◽  
A.V. Shelyakov
Keyword(s):  
Thin Film ◽  
Pulsed Laser Deposition ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Thin Film Catalysts

Structure and Magnetotransport Properties of La2/3Ca1/3MnO3 Thin Films Prepared by Pulsed Laser Deposition

1998 ◽  
Vol 526 ◽  
Author(s):  
O.I. Lebedev ◽  
G. van Tendeloo ◽  
S. Amelinckx ◽  
B. Leibold ◽  
H.-U. Habermeier ◽  
...  
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Displacement Vector ◽  
Substrate Surface ◽  
Pulsed Laser ◽  
Atomic Emission ◽  
Growth Conditions ◽  
Lattice Parameter ◽  
Laser Deposition ◽  
Parameter Mismatch

AbstractLa1-xCaxMnO3-δ (LCMO) thin films are grown by pulsed laser deposition on a (100) SrTiO3 substrate at temperatures between 530°C and 890°C. The magnetotransport properties show a high negative magnetoresistance and a shift of the maximum of the R(T) curve as function of temperature. The Curie temperature changes with deposition temperature and film quality in the range of 100-220K. The film quality is characterised by X-ray diffraction and transmission electron microscopy (TEM); film and target compositions were verified by atomic emission spectroscopy. The local structure of the film depends on the growth conditions and substrate temperature. TEM reveals a slight distortion of the film leading to a breakdown of the symmetry from orthorhombic to monoclinic. At the highest growth temperatures, a well defined interface is observed within the LCMO film, parallel to the substrate surface; this interface divides the film into two lamellae with a different microstructure. The lamella close to the substrate is perfectly coherent with the substrate, suggesting that it is strained as a result of the lattice parameter mismatch; the upper lamella shows a typical domain structure with unusual translation interfaces characterised by a displacement vector of the type 1/2 [010]m and 1/2[001]m when referred to the monoclinic lattice.

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