Solid Source Precursor Research Articles

The effect of nickel oxide in the direct growth of MnOx on Ni foam by chemical vapor deposition

Manganese oxide has emerged as a promising material for use as a charge storage electrode material. In this work, we demonstrate the low-pressure chemical vapour deposition (CVD) growth of manganese oxide conformal coatings on Ni-foams utilising an MnCl2 solid source precursor, utilising an oxide formed on the surface of the Ni-foam as an oxygen reservoir for the synthesis of a predominantly MnO x layer. The resulting MnO x layer is highly dependent on sample pre-treatment, owing to modifications in the Ni oxide layer. The phase structure, electronic states, morphology, and electrochemical analysis were determined by x-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning-electron microscopy (FE-SEM), and capacitance–voltage (CV) measurements. The importance of the oxide layer is demonstrated by modifying the thickness of the NiO layer over the Ni foam, with clear changes in the resultant structure, morphology, and areal capacitance, with the highest performance MnO x coating found to be obtained without any oxide removal from the Ni foam substrate.

Some properties of metal organic chemical vapor deposited (MOCVD) manganese nitride thin films (MnxNy) obtained using a single precursor of Tetraamminebis-(hexamethylenetetrammine) manganese (II) chloride [Mn (HMTA)2(NH3)4] Cl2

A single solid source precursor, tetraamminebis-(hexamethylenetetrammine) Manganese (II) Chloride [Mn (HMTA)2(NH3)4] Cl2 was prepared and thin films of manganese nitride MnxNy were grown on soda-lime glass substrates at varied temperature using Metal Organic Chemical Vapor deposition (MOCVD) technique. The Energy Dispersive X-ray (EDX) spectra showcased the thin film constituent's elements as Mn and N in weight ratios which further confirmed absolute stoichiometry. The Fourier Transform Infra-Red (FTIR) spectrometry carried out on the precursors revealed the presence of functional groups between 1600 and 3200 cm−1 in the precursors, and ligands were mostly removed by pyrolysis process of the MOCVD at a temperature range of 300–340 °C. Due to the thermal deposition technique employed, FTIR spectrographs of MnN thin films exhibit coalescences between grains and a clear bond disintegration. Structural characterization using X-ray diffraction (XRD) revealed that the synthesized MnN thin film possesses a simple cubic structure with crystallite sizes estimated by employing Scherer's formula and Hall–Williamson plots. The scanning electron microscopy (SEM) showed columnar pattern and mesopores with the substrate covered by smaller, spherical grain particles having an estimated size of 3–4 nm, and large, structured particles with an estimated size of 10.0–20.0 nm placed on top of the smaller grain size particles. The indirect optical bandgap value of the MnN thin film was confirmed by optical absorbance analysis to be 2.75 eV and 3.0 eV at temperatures of 300 and 340 °C, respectively.

Opto-electronic properties of copper-zinc-sulfide thin films grown via metalorganic-chemical vapor deposition technique at different flow rates

In this work, copper zinc sulfide (CZS) ternary thin films were prepared from the pyrolysis of a Bis-(morpholinodithiato-s,s’)-Cu-Zn precursor using metal-organic chemical vapor deposition technique maintained at 450 °C in ambient nitrogen as the carrier gas. The deposition flow rate was varied to study its effect on the optoelectronic properties of CZS films. The particle-induced x-ray emission technique (PIXE) of the prepared single solid source precursor shows the presence of copper, zinc, and sulfur. The Fourier transform infrared spectrophotometer of the precursor reveals the metal-metal bond attachment to the ligand at a very low wavenumber. The XRD spectra reveal the formation of the hexagonal closed-packed structure of CZS films with a preferred orientation along the [111] direction. The film crystallite size is found to increase from 10.4 to 12.2 nm as the flow rate increases, while the dislocation density and stress decrease as the deposition flow rate increases. The SEM analysis revealed an improvement in the growth rate of the grains as the flow rate increased. The transmittance of the deposited CZS films was found to increase from 58% to 84.2% in the infrared region with an increase in band gap from 3.08–3.64 eV as the flow rate increased. The deposited film shows ohmic properties and an increase in conductivity from 0.243 to 0.847 ( while the resistivity decreases as the flow rate increases. These observations provide room for the deposited CZS film to serve as a potential material for optoelectronics and window layer solar cell devices.

Deposition of stoichiometry – tailored amorphous Cu-S thin films by MOCVD technique

ABSTRACT Deposition technique and associated deposition parameters play significant roles in determining the stoichiometry of thin films, and consequently, their properties. Herein, Cu-S thin films were deposited on a sodalime glass substrate via metal organic chemical vapour deposition (MOCVD) at temperatures between 350 and 450°C using a single solid source precursor. The deposited Cu-S films were characterized using Rutherford backscattering spectroscopy (RBS), X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–visible spectrophotometry, and four-point probe technique. RBS characterization revealed that the films are non-stoichiometry while thickness increased from 480 to 655 nm as deposition temperature increased. SEM revealed micrographs that are temperature-dependent. A direct band gap value between 2.75 and 3.80 eV was obtained as the deposition temperature increased. Electrical characterization showed ohmic characteristics in which, resistivity decreased from 18.50 × 10−3 Ωcm to 8.20 × 10−3 Ωcm as deposition temperature increased.

A 1D silver(I) coordination polymer of a new hydrozone-hydrazide ligand: Spectral, structural, emission, and anti-bacterial properties and its application as a solid source precursor for silver oxide nanoparticles

A new one-dimensional (1D) coordination polymer of composition [Ag(L)(NO3)]n was synthesized by a reaction of silver(I) nitrate with a new hydrazone-hydrazide ligand (L) derived from 2-acetyl furan and ethyl hydrazine carboxylate. Both the ligand, L, and the silver(I) complex were characterized using elemental analysis, electron impact mass spectrometry (EI-Mass), infrared (IR), proton nuclear magnetic resonance (1H NMR), ultraviolet–visible (UV–Vis) spectroscopy, and emission spectroscopy analyses. Single-crystal X-ray diffraction study shows that the structure of the silver(I) complex consists of 1D polymeric chains in which silver(I) ion is in four coordination complexes arising from one N, O-chelating L and two O, O′-bridging nitrate anions. The complex emitted energy around 360 nm and was used as a single precursor for synthesis of silver oxide nanoparticles (Ag2O NPs). From transmission electron microscopy (TEM) and higher-resolution TEM (HR-TEM) images, the as-prepared Ag2O NPs were nearly spherical in shape with average particle sizes of approximately 22–24 nm. Anti-bacterial properties of both the ligand and the metal complex were studied.

Toward Low-Temperature Solid-Source Synthesis of Monolayer MoS2

Two-dimensional (2D) semiconductors have been proposed for heterogeneous integration with existing silicon technology; however, their chemical vapor deposition (CVD) growth temperatures are often too high. Here, we demonstrate direct CVD solid-source precursor synthesis of continuous monolayer (1L) MoS2 films at 560 °C in 50 min, within the 450-to-600 °C, 2 h thermal budget window required for back-end-of-the-line compatibility with modern silicon technology. Transistor measurements reveal on-state current up to ∼140 μA/μm at 1 V drain-to-source voltage for 100 nm channel lengths, the highest reported to date for 1L MoS2 grown below 600 °C using solid-source precursors. The effective mobility from transfer length method test structures is 29 ± 5 cm2 V-1 s-1 at 6.1 × 1012 cm-2 electron density, which is comparable to mobilities reported from films grown at higher temperatures. The results of this work provide a path toward the realization of high-quality, thermal-budget-compatible 2D semiconductors for heterogeneous integration with silicon manufacturing.

Effect of alkyl substituent on molecular configuration in a Cu(II) complex: Synthesis of Cu and CuO nanoparticles using a single, solid-source precursor

A new hydrazone-type ligand, methyl 4-(pyridine-4yl-methylene) hydrazinecarboxylate (C8H9N3O2; 4-pymc) and its Cu(II) complex [Cu(4-pymc)2(CH3COO)2(H2O)] (1) were prepared and characterized. The structure of 1 comprises monomers in which Cu is five-coordinated with a distorted square pyramidal structure. Oxygen atoms of two monodentate acetate anions and a pair of nitrogen atoms from pyridine rings form the basal plane. The apical position is filled by a water molecule. Further, the TEM images demonstrated successful preparation of both Cu (~35 nm) and CuO (~95 nm) nanoparticles (NPs) using the single source as-prepared Cu(II) complex via a thermal decomposition approach simply by changing the atmospheric conditions (i.e., vacuum and air atmospheres) under which the Cu(II) complex was calcined for 1 h at 400 °C. Furthermore, the TG-DTA studies indicate that 1 underwent endo- followed by exo-thermic decomposition to form CuO as the end residue in an air atmosphere. The production of Cu and CuO NPs was corroborated by powder x-ray diffraction (PXRD) analysis. The sharp and high intensity PXRD peaks of the calcined samples corroborated that the formed NPs had no impurity and high crystallinity. Furthermore, both ligand and Cu(II) complex showed photoluminescence properties. Also, we demonstrated that the prepared 1 can act as a single, solid-source precursor to form both Cu and CuO NPs.

Compositional, Structural, Morphological, Optical and Electrical Property Evolutions in MOCVD Cu-Zn-S Thin Films Prepared at Different Temperatures Using a Single Solid Source Precursor

Bis-(morpholinodithiato-s,s′)-Cu-Zn was synthesized as a single solid source precursor and characterized using particle-induced x-ray emission (PIXE), Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). Cu-Zn-S thin film was deposited on sodalime glass substrate using metal organic chemical vapor deposition (MOCVD) technique at temperatures ranging from 360°C to 450°C. The thin films were characterized using Rutherford backscattering spectroscopy (RBS), x-ray diffraction (XRD), scanning electron microscopy (SEM), UV–visible spectroscopy and four-point probe technique. PIXE of the precursor confirmed the presence of the expected elements that can lead to deposition of Cu-Zn-S thin film while FTIR confirmed that the organic ligands were attached to the metals. DSC showed that the precursor is thermally stable and can pyrolyze at temperature between 340°C and 460°C. RBS analysis of the films showed that there was no substantial deposition at 360°C while other films showed various stoichiometry and thickness. XRD analysis of the films showed that films deposited at 360°C and 380°C are amorphous, while those deposited between 400°C and 450°C showed peaks, in which the crystal size decreased as the deposition temperature increased. The SEM micrographs showed that the morphology of the films is temperature dependent and as deposition temperature increased larger secondary grains dissociated into smaller grains that are closely packed, without cracks and holes. Optical characterization showed that the films exhibited high transmittance, which fairly increased as the deposition temperature increased. A direct band gap value between 2.49 eV and 2.92 eV was obtained as deposition temperature increased. Urbach energy also increased from 0.87 eV to 1.51 eV, while the steepness parameter decreased as the deposition temperature increased. The electrical characterization showed that the resistivity of the films decreased as the deposition temperature increased while the I–V plot showed a rectifying character.

Single solid source precursor route to the synthesis of MOCVD Cu-Cd-S thin films

Bis-(morpholinodithiato-s,s′)-Cu-Cd was synthesized from appropriate reagents as a single solid source precursor and characterized using particle induced x-ray emission (PIXE), Fourier transform infrared (FTIR) spectroscopy and differential thermal analysis (DTA). Cu-Cd-S thin films were deposited on sodalime glass substrate using MOCVD technique at temperatures in the range 360 °C–450 °C. The films were further characterized using Rutherford backscattering spectroscopy (RBS), x-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible spectroscopy and four-point probe technique. PIXE revealed that the synthesized precursor contained the expected elements which led to the successful deposition of the Cu-Cd-S thin films. FTIR ascertained that the organic ligand actually attached to the metals. DTA analysis showed that the synthesized precursor was thermally stable and could pyrolyzed around 300 and 500 °C. RBS of the deposited films showed that the stoichiometry and the thickness depended on deposition temperature. XRD analysis revealed that the films deposited at 360 and 380 °C are amorphous while those deposited at 400 °C to 450 °C showed peaks, which supported the possible co-existence of CuS and CdS as Cu-Cd-S, with an improvement in the crystallinity as substrate temperature increased. SEM showed that the films are uniform and crack-free, in which the morphology strongly depended on substrate temperature. Optical analysis revealed that the films have high absorbance in the UV region and high transmittance in the visible and near infrared region, in which direct band gap energy of 2.36 to 2.14 eV was obtained as deposition temperature increased. Other optical parameters such as Urbach energy, refractive index, extinction coefficient, dielectric constant also increased as the deposition temperature increased. Electrical analysis showed that resistivity is temperature dependent as it reduced as deposition temperature increased.

Optical, Structural and Electrical Properties of Aluminum Doped Zinc Oxide Thin Films by MOCVD Technique

Thin films of aluminum-doped ZnO (AZO) were deposited by metal organic chemical vapor deposition from a single solid source precursor, aluminum zinc acetylacetonate. The AZO thin films were deposited on a sodalime glass substrate at different substrate temperatures ranging from 390°C to 450°C. Results were characterized using Rutherford backscattering spectroscopy (RBS), scanning electron microscopy (SEM) with energy dispersive x-ray (EDS) facility attached to it, x-ray diffraction (XRD), UV–Visible spectrometry and a four point probe method (with an applied magnetic field). While RBS determined the thickness and elemental composition of the films, the presence of the expected elements in the films was also corroborated by EDS. The average thickness of the thin films was determined to be 133 nm. SEM micrographs revealed that the films were composed of continuously and uniformly distributed crystalline grains without any cracks. XRD analysis showed that the films were polycrystalline with a structure belonging to ZnO hexagonal wurtzite and grain size ranging from 27.50 nm to 41.30 nm. The optical transmittance of AZO films deposited at different temperatures varied from 75% to 95% in the range of wavelength 400–700 nm, with an optical band gap energy value between 3.27 eV and 3.30 eV. The electrical characterization of AZO films deposited at different substrate temperatures revealed resistivity values between 0.07 Ω cm and 0.01 Ω cm. The mobility was not the same for all the films, so also carrier concentration. The physico-chemical characterization showed that the AZO film deposited at temperature 420°C possessed the best properties among the three samples.

Morphological and optical study of thin films of CuAlS2 deposited by metal organic chemical vapour deposition technique

Single solid source precursor of Copper–Aluminium dithiocarbamate was prepared and characterized by infrared spectroscopy. Thin films of copper aluminium sulphide were deposited on the substrate (soda lime glass) using metal organic chemical vapour deposition (MOCVD) technique within temperature ranges of 420 and 450 °C through the pyrolysis of the prepared precursor. Morphological and optical characterizations were then carried out. Morphological study carried out using scanning electron microscopy (SEM) showed that the deposited films are dense and polycrystalline in nature, uniform with the particle size distribution of the grains decreasing with increase in temperature. A direct optical energy gap of 3.28 and 2.88 eV were obtained for films deposited at 420 and 450 °C respectively. Other optical constants were found to increase as temperature increased.

Optical and Electrical Properties of Copper Doped Cadmium Oxy-Sulphide Quaternary Thin Films by MOCVD Technique

A prepared single solid source precursor was used for the deposition of copper doped oxy-sulphide thin films on glass substrate by MOCVD technique. This was achieved by the pyrolysis of the prepared precursors at 420&deg;C with a flow rate of 2.5 dm³/min for 2 hours. The deposited films were characterized using Rutherford Backscattering Spectroscopy (RBS), Scanning Electron Microscopy (SEM), UV-visible spectrophotometry and four point probe method. RBS analysis showed that the expected elements are present while the thickness was estimated to be 889 nm. The SEM images of the deposited film showed a fine structure with densely packed grains of uniform grain size of about 80 nm, well distributed throughout the entire substrate which is polycrystalline in nature. The film revealed an average transmittance of 80% in the visible region with a direct bandgap of 2.41 eV. The absorbance of the film was observed to be low in the visible and near-infrared regions, and high in UV region. The values of 1 <img width="80" height="16" src="http://article.sciencepublishinggroup.com/journal/123/1231164/image001.png"/>&nbsp;and <img width="62" height="16" src="http://article.sciencepublishinggroup.com/journal/123/1231164/image002.png"/>&nbsp;were obtained as the sheet resistance and resistivity of the film respectively. The deposited quaternary thin film is found to be a promising candidate as window layer and absorber layer for cost effective photovoltaics.

Synthesis and Characterization of Metal Organic Chemical Vapour Deposited Copper Titanium Oxide (Cu-Ti-O) Thin Films from Single Solid Source Precursor

Thin films of copper titanium oxide were deposited by metal organic chemical vapour deposition technique from the synthesized single solid source precursor, copper titanium acetylacatonate Cu [Ti(C5H7O2)3] at the deposition temperature of 420°C. The deposited films were characterized using Rutherford Backscattering Spectroscopy, Scanning Electron Microscopy with Energy Dispersive X-Ray facility attached to it, X-Ray Diffractometry, UV-Visible Spectrometry and van-der Pauw Conductivity measurement. Results show that the thickness of the prepared film is determined as 101.236 nm and the film is amorphous in structure, having average grain size of approximately 1 μm. The optical behaviour showed that the absorption edge of the film was at 918 nm near infrared with corresponding direct energy band gap of 1.35 eV. The electrical characterization of the film gave the values of resistivity, sheet resistance and conductivity of the film as 3.43 × 10-1 Ω-cm, 3.39 × 106 Ω/square and 2.91 (Ω-cm)-1 respectively.

Synthesis and Characterization of Metal Organic Chemical Vapour Deposited Copper Titanium Oxide (Cu-Ti-O) Thin Films from Single Solid Source Precursor

Thin films of copper titanium oxide were deposited by metal organic chemical vapour deposition technique from the synthesized single solid source precursor, copper titanium acetylacatonate Cu [Ti(C5H7O2)3] at the deposition temperature of 420°C. The deposited films were characterized using Rutherford Backscattering Spectroscopy, Scanning Electron Microscopy with Energy Dispersive X-Ray facility attached to it, X-Ray Diffractometry, UV-Visible Spectrometry and van-der Pauw Conductivity measurement. Results show that the thickness of the prepared film is determined as 101.236 nm and the film is amorphous in structure, having average grain size of approximately 1 μm. The optical behaviour showed that the absorption edge of the film was at 918 nm near infrared with corresponding direct energy band gap of 1.35 eV. The electrical characterization of the film gave the values of resistivity, sheet resistance and conductivity of the film as 3.43 × 10-1 Ω-cm, 3.39 × 106 Ω/square and 2.91 (Ω-cm)-1 respectively.

Enhanced Light Absorption in Textured Metal Organic Chemical Vapour Deposited (MOCVD) CdO Thin Films

ABSTRACTThe Single Solid Source precursor Cadmium Acetylacetonate, Cd[C5H7O2]2 was prepared and Cadmium Oxide thin films were deposited on Sodalime glass substrate using Metal Organic Chemical Vapour Deposition (MOCVD) technique at deposition temperature of 420 oC The films were characterized using Scanning Electron Microscopy (SEM) with Energy Dispersive XRay (EDX) facility attached to it, X-Ray Diffractometry (XRD) and UV-visible spectrometry. SEM micrographs showed the formation of textured surface with identifiable cubic and hexagonal structures, having average grain size greater than 1 μm. XRD studies indicated the formation of polycrystalline cubic CdO phase with preferred orientation in (111) plane. A direct optical band gap of 2.10 eV was obtained from the analysis of the UV-visible spectrum with an enhanced light absorption in 750 – 1000 nm spectrum range. This enhancement is as a result of light trapping by the textured crystalline structure.

MOCVD of Molybdenum Sulphide Thin Film Via Single Solid Source Precursor Bis-(Morpholinodithioato-s,s’)-Mo

A single solid source precursor bis-(morpholinodithioato-s,s’)-Mo was prepared and molybdenum sulphide thin film was deposited on sodalime glass using Metal Organic Chemical Vapour Deposition (MOCVD) technique at deposition temperature of 420?C. The film was characterized using Rutherford Backscattering Spectroscopy (RBS), Ultraviolet-Visible Spectroscopy, Four point probe technique, Scanning Electron Mi-croscopy (SEM), X-ray Diffractometry (XRD) and Atomic Force Microscopy (AFM). A direct optical band gap of 1.77 eV was obtained from the analysis of the absorption spectrum. The sheet resistance was found to be of the order of 10P–5P ΩP–1P?cmP–1P. SEM micrographs of the films showed the layered structure of the film with an estimated grain size that is less than 2 µm while XRD indicates parallel orientation of the basal plane to the substrate surface.

Synthesis and Some Properties of Metal Organic Chemical Vapour Deposited Molybdenum Oxysulphide Thin Films

Molybdenum oxodithiocarbamate was prepared as a single solid source precursor for molybdenum oxysulphide thin films which were deposited on sodalime glass substrates using metal organic chemical vapour deposition (MOCVD) technique at a temperature of 420°C. Rutherford backscattering spectroscopy (RBS) was used to determine the elemental composition of the film which showed that the films contained large amounts of oxygen. The large amount of oxygen was attributed to the large abundance of oxygen in the starting material. A direct optical energy gap of 3.31 eV was obtained from the analysis of the absorption spectrum. The scanning electron microscopy (SEM) micrographs of the films showed that the films were continuous and porous. An estimated average size of the grains was below 5 μm. X-ray diffraction (XRD) showed that the deposited films were crystalline in nature.

Bubbler for constant vapor delivery of a solid chemical

Indium containing compounds are used in many electronic and optoelectronic devices. Examples vary from InAlGaP/InGaP materials for red emitters and HBTs, to InGaAs/InAlGaAs/InGaAsP for long-wavelength telecommunication lasers. For metalorganic chemical vapor deposition (MOCVD) of these devices, the chemical precursor used for epitaxial growth is generally trimethylindium (TMIn). TMIn is a solid source precursor and therefore has several issues associated with its reproducible and reliable delivery from the bubbler to the reactor, especially at high molar flow rates. In this work we report results on extremely stable delivery of TMIn under various experimental conditions using a unique bubbler design which overcomes most of the delivery problems associated with solid sources. With this bubbler, named the Hiperloop, we are able to obtain stable TMIn flux with a consumption of greater than 92–95% at various experimental conditions. We concentrate on conditions which are considered challenging but can deliver high throughput such as low pressures, high carrier gas flow rates, and high source temperatures.

Preparation and characterization of MOCVD thin films of indium tin oxide

Indium Tin Oxide (ITO) was deposited by pyrolysis of mixed metal acetylacetonate (a single solid-source precursor). This study demonstrates that the properties of the as-deposited film depend on the deposition temperature. Films with a resistivity of 7.2×10 −4 Ω cm , a visible transmission of over 80%, and a direct optical energy gap of 3.76 eV were deposited.

Preparation and characterization of MOCVD thin films of zinc sulphide

Thin solid films of stoichiometric zinc sulphide on soda lime glass and stainless steel was deposited by the pyrolysis of bis-(morpholino dithioato-s,s′)zinc (C 10H 16N 2O 2S 4Zn) (a single solid source precursor). The band gap of 3.67 eV was obtained by optical absorption spectroscopy. The composition, stoichiometry and thickness were determined by energy dispersive X-ray fluorescence (EDXRF) and Rutherford backscattering spectroscopy (RBS) and the absence of organic remnants in the film is demonstrated by IR spectroscopy and RBS.