CZTS thin film solar cells on flexible Molybdenum foil by electrodeposition-annealing route

Earth-abundant and non-toxic Kesterite-based Cu2ZnSnS4 (CZTS) thin film solar cells are successfully fabricated on flexible Molybdenum (Mo) foil substrates by an electrodeposition-annealing route. A well-adherent, densely packed, homogeneous, compact, and mirror-like CZT precursor is initially produced through electrodeposition by using a rotating working electrode. Subsequently, the co-electrodeposited CuZnSn (CZT) precursor is sulfurized in quartz tube furnace at 550 °C for 2 h in N2 atmosphere with the presence of elemental sulfur in order to form CZTS. Different characterization techniques like XRD, SEM, HR-TEM, Raman, and Photoluminescence demonstrate that almost phase-pure CZTS formed after sulfurization. A flexible Al/Al-ZnO/i-ZnO/CdS/CZTS/Mo foil solar cell is produced, where CdS is deposited by chemical bath deposition and transparent conducting oxide (TCO) is deposited by DC sputtering. The CZTS solar device shows a 0.55% power conversion efficiency on flexible Mo foil substrate and it constitutes the first prototype of this kind of solar cell produced by electrodeposition-annealing route without any surface modification of the Mo substrate. Graphic abstract

Investigation of Novel Te precursor (i-C3H7)2Te for MoTe2 Fabrication

ABSTRACTWe report the investigation on the properties of a novel Te precursor (i-C3H7)2Te and its effectiveness in fabricating MoTe2. The vapor pressure of the precursor was obtained by measuring the pressure as a function of its temperature in a sealed chamber. As a result it showed a high vapor pressure of 552.1 Pa at room temperature. The decomposition of the precursor was also investigated using DFT calculation. It was shown that the most likely reaction during the course of the decomposition of (i-C3H7)2Te is (i-C3H7)2Te → H2Te + 2 C3H7. The effectiveness of the precursor on the fabrication of MoTe2 was also investigated. Sputter-deposited MoO3 was tellurized in a quartz-tube furnace at the temperature up to 440°C. The resulting film showed that the 80% of the original MoO3 was tellurized to form MoTe2. It was also shown that further optimization of tellurization is required in order to prevent formation of metal Mo and elemental Te.

Growth of AlInN films via elemental layers annealing at different temperatures

This work investigates the growth of AlInN films on Si (100) substrates through the annealing of Al and InN stacking layers in the temperature range 200[Formula: see text]C to 800[Formula: see text]C. The Al/InN layers were prepared on Si (100) substrates using RF magnetron sputtering technique at 100[Formula: see text]C. The layers were annealed in a quartz tube furnace at 200[Formula: see text]C, 400[Formula: see text]C, 600[Formula: see text]C and 800[Formula: see text]C for six hours. Structural features of the films were examined through XRD whereas the surface morphology and composition of the films were studied through FESEM and EDS, respectively. The FESEM and EDS cross-sectional analyses of the films were also conducted to observe the mixing of Al/InN stacking layers. XRD patterns revealed the formation of polycrystalline AlInN films whereas the FESEM and EDS cross-sectional results indicated that the mixing of Al/InN stacked layers became more prominent with increase of the annealing temperature. Surface roughness of the films studied through AFM also exhibited an increasing trend with increase of the annealing temperature.

Removal of Pollutants from High Polychlorinated Biphenyl Level Contaminated Soil at Different Thermal Treated Time

High contaminated level of polychlorinated biphenyl (PCBs) in soil could not be easily removed by routine method. Since thermal treatment technology becomes a promising method especially for removal of volatile organic compounds, it has not yet been widespread in China for some technical and economic reasons. Experiments were conducted in a horizontal quartz tube furnace with nitrogen as the unique carrier gas, and heating temperature was set at 500oC with retention time of flue gas desorbed from soil was about 1 min. It has been found that total removal efficiency of PCBs from soil increased with the heating time was prolonged. Thermal treated time of 60 min seems suitable for the removal of PCBs, with the removal efficiency of 95.8% in solid phase. It has also been concluded that the removal mechanism of PCBs from soil endures dechlorination and destruction reactions with anticipation of catalytic metals. Normal gaseous pollutants desorbed from soil were also studied, H2O evaporation was favored with at the beginning of thermal process; after H2O evaporation, the organic matters began to decompose; when the thermal treated time was longer than 20 min, the desorption of the normal gaseous pollutants were almost finished (except for NH3).

Synthesis and Characterization of YB66 Nanowires

The objective of the current research is to synthesize yttrium boride (YB66) nanowires. Catalyst assisted growth of the nanowires under the vapor-liquid-solid (VLS) synthesis method was performed in a quartz tube furnace. The pyrolysis of diborane (B2H6) gas over yttrium oxide (Y2O3) powders with a thermally coated layer of nickel catalyst was carried out. The reaction conditions were at 925o C and a pressure of 390 mTorr with varying reaction times. SEM analysis has shown the growth of nanowires with diameters around 400 nm. A catalyst particle was also seen at the tip of the nanowires, confirming growth by the VLS mechanism. Other analysis techniques that were used include Raman spectroscopy and TEM analysis. The Raman spectra of the nanowires were in good agreement with a Raman spectrum obtained on a YB66 single crystal. However, no other evidence was obtained that the nanowires contained yttrium or that the nanowires consisted of YB66.

Seeding Solid Phase Crystallization of Amorphous Silicon Films with Embedded Nanocrystals

ABSTRACTSilicon nanocrystals with diameters up to 30 nm are used as nucleation seeds for fast solid phase crystallization of amorphous silicon films. Purely amorphous films required an incubation time of up to 12 hours at 600°C prior to the onset of nucleation, while films with nanocrystals embedded between layers of amorphous silicon grew immediately upon annealing in a quartz tube furnace. Structural characterization was performed by heated-stage transmission electron microscopy and Raman spectroscopy.

Synthesis and Characterization of Calcium Hexaboride (CaB6) Nanowires

The objective of the current research was to synthesize calcium hexaboride (CaB6) nanowires for analysis of hydrogen storage materials. Catalyst assisted growth of nanowires under the Vapor-Liquid-Solid synthesis method was performed in a quartz tube furnace. The pyrolysis of diborane (B2H6) gas over calcium oxide (CaO) powders with a thermally coated layer of nickel catalyst was carried out. SEM and TEM analysis have shown the generation of nanowires although calcium and boron did not react in a 1:6 ratio, though 1:4 and 1:8 ratios were achieved. Several types of nanowire compositions were found under EELS and EDX analyses, including calcium and oxygen coated boron nanowires. Overall, it was found that a decrease in the amount of nickel catalyst used is correlated to a decrease in the diameters of the nanowires. A higher diborane gas flow rate into the reaction chamber was also correlated to more abundant nanostructures in the sample.

Synthesis and Characterization of High Quality InN Nanowires and Nano-networks

ABSTRACTHigh quality InN nanowires have been synthesized in a horizontal quartz-tube furnace through direct reaction between metallic Indium and Ammonia using Nitrogen as the carrier gas. Thin film of Au on SiO2/Si substrate has been used as the catalyst layer, facilitating vapor-liquid-solid growth of the nanostructures. The nanowires were grown at a very fast rate of up to 30 μm/hr. Smooth and horizontal nanowire growth was achieved only with nanoscale catalyst patterns, while large area catalyst coverage resulted in uncontrolled and three-dimensional growth. The InN nanowires, which were usually covered with a thin shell layer of In2O3, grew along [110] direction, with overall diameters 20 - 60 nm and lengths 5 - 15 μm. The synthesized nanowires bent spontaneously or got deflected from other nanowires at multiples of 30 degrees forming nano-networks. The catalyst particles for the NWs were found mostly at the sides of the NW apex which helped them to bend spontaneously or get deflected from other NWs at angles which were multiples of 30 degrees. The NW based FETs with a back-gated configuration have already been investigated. The gate-bias dependent mobility of the NWs ranged from 55 cm2/Vs to 220 cm2/Vs, and their carrier concentration was ∼1018 cm−3.

Fabrication of Single Crystalline Cadmium Nanowires by a Facile Low Temperature Vapor Phase Method

Single-crystalline cadmium nanowires were successfully fabricated by vaporization of cadmium metal powders in a horizontal quartz tube furnace at 250 °C. The vaporization was carried out for 30 minutes and yielded nanowires of diameters of 80 to 250 nm and lengths up to several tens of microns. The nanowires were deposited on a Si (111) substrate kept at the lower temperature zone (150–175 °C) of the furnace. When the deposition temperature was lower than this, hexagonal nanodisks were produced. The possible mechanism for the formation of the obtained nanostructures is discussed.