Abstract:Silicon (Si) films were obtained through aluminothermic reduction of the quartz (SiO2) substrates, where the surface of the quartz in contact with the deposited aluminum (Al) layer has been converted to film Si during high-temperature annealing following reduction reaction. X-ray diffraction (XRD) patterns and Raman spectra show dominating peaks corresponding to elemental Si in the obtained films. Energy dispersive spectroscopy (EDS), as well as XRD of the obtained Si layer, suggests that reduction products co… Show more
“…CSS proceeds under pressure in normal ambient air [22] and is thus different from a similar process with sputtered Al on quartz performed at 650 or 700 °C under vacuum conditions, resulting in a layer of Si mixed with oxides of Al-related phases. [26] For trace analysis of the silicon layer secondary ion mass spectrometry (SIMS) was performed. Depth profiles of impurity concentrations in CSS silicon were analyzed by sputtering with 5.5 keV O 2 + ions on the same sample investigated in the SEM/EDX analyses.…”
Section: Resultsmentioning
confidence: 99%
“…CSS proceeds under pressure in normal ambient air [ 22 ] and is thus different from a similar process with sputtered Al on quartz performed at 650 or 700 °C under vacuum conditions, resulting in a layer of Si mixed with oxides of Al‐related phases. [ 26 ]…”
The study describes synthesis and characterization of > 10 µm thick multicrystalline (mc), highly oriented, p‐doped silicon layers by aluminothermic reduction of low‐cost soda‐lime glass. X‐ray diffraction shows a highly preferred (111)‐orientation and excellent crystallinity. Low compressive stress and very good crystallinity are confirmed by the peak position and width of the Raman LO‐phonon line, approaching the one of bulk single‐crystalline wafer material. Due to strong bonding to the glass substrate layer, spalling is not observed. A conductive aluminum‐rich oxide layer is formed underneath the silicon, serving as an electrical back‐contact for electronic devices. Using secondary ion mass spectrometry very low concentrations of 1014–1015 cm−3 of impurities are found originating from the soda‐lime glass with an iron content below the detection limit. Furthermore, a plateau‐like, very homogenous Al concentration of ≈4 × 1018 cm−3 over a thickness of ≈10 µm is found, which corresponds to the solubility of Al in Si at the process temperature. Complete electronic activation within the plateau region is confirmed by carrier concentration measurements using electrochemical capacitance–voltage profiling and Raman spectroscopy. Hole concentrations in the range of few 1018 cm−3 are beneficial for the p‐type base material of full‐emitter cell mc‐silicon photovoltaic devices.
“…CSS proceeds under pressure in normal ambient air [22] and is thus different from a similar process with sputtered Al on quartz performed at 650 or 700 °C under vacuum conditions, resulting in a layer of Si mixed with oxides of Al-related phases. [26] For trace analysis of the silicon layer secondary ion mass spectrometry (SIMS) was performed. Depth profiles of impurity concentrations in CSS silicon were analyzed by sputtering with 5.5 keV O 2 + ions on the same sample investigated in the SEM/EDX analyses.…”
Section: Resultsmentioning
confidence: 99%
“…CSS proceeds under pressure in normal ambient air [ 22 ] and is thus different from a similar process with sputtered Al on quartz performed at 650 or 700 °C under vacuum conditions, resulting in a layer of Si mixed with oxides of Al‐related phases. [ 26 ]…”
The study describes synthesis and characterization of > 10 µm thick multicrystalline (mc), highly oriented, p‐doped silicon layers by aluminothermic reduction of low‐cost soda‐lime glass. X‐ray diffraction shows a highly preferred (111)‐orientation and excellent crystallinity. Low compressive stress and very good crystallinity are confirmed by the peak position and width of the Raman LO‐phonon line, approaching the one of bulk single‐crystalline wafer material. Due to strong bonding to the glass substrate layer, spalling is not observed. A conductive aluminum‐rich oxide layer is formed underneath the silicon, serving as an electrical back‐contact for electronic devices. Using secondary ion mass spectrometry very low concentrations of 1014–1015 cm−3 of impurities are found originating from the soda‐lime glass with an iron content below the detection limit. Furthermore, a plateau‐like, very homogenous Al concentration of ≈4 × 1018 cm−3 over a thickness of ≈10 µm is found, which corresponds to the solubility of Al in Si at the process temperature. Complete electronic activation within the plateau region is confirmed by carrier concentration measurements using electrochemical capacitance–voltage profiling and Raman spectroscopy. Hole concentrations in the range of few 1018 cm−3 are beneficial for the p‐type base material of full‐emitter cell mc‐silicon photovoltaic devices.
“…The Fe:Si ratios of each film were quantified from these EDX peaks as summarized in Table 1 , where the composition of Fe 3 Si films turns into that of the FeSi at 600 °C and then FeSi 2 's composition at 800 °C, helping to cement the implication of atomic diffusion as the culprit of the drastic change in the film's properties. The increasing appearance of Si(111) after RTA at increasing T RTA value is likely to originate from the fusion between films and substrate, as backed up by the contradictory results of surface profiling and cross-sectional imagery [ 31 ]. Fig.…”
“…The silicon element in TAD 3D was mainly distributed in the porous area. The dense ceramic layer at the interface may be due to the fact that during the composite process, the aluminum melt reacted with SiO 2 in TAD 3D to reduce SiO 2 near the interface to the Si, and the Si diffused into the aluminum melt [30]. It may also be caused by the unevenness of the ceramic itself.…”
This study created ceramic preforms with a 3D network structure (TAD3D) by using treated aluminum dross (TAD) and kaolin slurry, with 30 ppi polyurethane foam as a template via the sacrificial template method. TAD3D/5A05Al composites were then produced via pressureless infiltration of 5A05Al aluminum alloy into TAD3D. The corrosion behavior and resistance of TAD3D/5A05Al in salt spray were assessed via neutral salt spray corrosion (NSS), scanning electron microscopy (SEM), potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS) tests. The results showed that after 24 to 360 h of NSS corrosion, the corrosion of the 5A05 matrix was primarily pitting, with pits expanding and deepening over time, and showing a tendency to interconnect. The main corrosion products were MgAl2O4, Al(OH)3, and Al2O3. As corrosion progressed, these products increased and filled cracks, pits, and grooves at the composite interface on the material’s surface. Corrosion products transferred to the grooves at the composite interface and grew on the ceramic surface. Corrosion products on the ceramic framework and the Al matrix can form a continuous passivation film covering the composite surface. PDP and EIS results indicated that the composite’s corrosion resistance decreased by 240 h but increased after that time. After 240 h, the surface passivation film can weaken corrosion effects and enhance the composite’s resistance, although it remained weaker than that of the uncorroded samples. Additionally, grooves at the composite interface deepened over time, with loosely structured corrosion products inside, potentially leading to severe localized corrosion.
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