A5091047690- Semiconductor materials and devices
- Silicon and Solar Cell Technologies
- Advancements in Semiconductor Devices and Circuit Design
- Semiconductor materials and interfaces
- Ferroelectric and Negative Capacitance Devices
- Silicon Nanostructures and Photoluminescence
- Integrated Circuits and Semiconductor Failure Analysis
- Semiconductor Quantum Structures and Devices
- Nanowire Synthesis and Applications
- Thin-Film Transistor Technologies
- Ion-surface interactions and analysis
University of Warwick
2022-2023
Abstract Surface passivating thin films are crucial for limiting the electrical losses during charge carrier collection in silicon photovoltaic devices. Certain dielectric coatings of more than 10 nm provide excellent surface passivation, and ultra‐thin (<2 nm) layers can serve as interlayers contacts. Here, SiO 2 , Al O 3 HfO created via plasma‐enhanced atomic layer deposition annealing. It is found that negatively charged exhibit passivation properties—exceeding those —with 0.9 annealed...
Understanding surface passivation arising from aluminium oxide (Al2O3) films is of significant relevance for silicon-based solar cells and devices that require negligible recombination. This study aims to understand the competing bulk lifetime effects which occur during activation atomic layer deposited Al2O3. We demonstrate maximum achieved on n- p-type silicon with at ∼ 450 °C, irrespective annealing ambient. Upon stripping Al2O3 re-passivating using a superacid-based technique, we find...
We have studied the mechanisms underpinning effective surface passivation of silicon with hafnium oxide (HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) thin films grown <italic xmlns:xlink="http://www.w3.org/1999/xlink">via</i> atomic layer deposition (ALD). Plasma-enhanced ALD O plasma and a tetrakis(dimethylamido)hafnium precursor was used to deposit 12 nm thick HfO at 200 °C on high-lifetime 5 Ωcm...
We investigate the potential of ultra-thin HfO2 films grown by atomic layer deposition for passivating contacts to silicon focusing on variations in film thickness and post-deposition annealing temperature. A peak passivation quality – as assessed carrier lifetime measurements is reported 2.2 nm thick annealed at 475 °C, which a surface recombination velocity <1 cm/s determined. For <2.2 thick, there marked decrease quality. X-ray diffraction highlights change from crystallised monoclinic...
Thin film dielectrics are ubiquitous in the manufacture of electronic devices and frequently deposited etched away at various stages device fabrication. We demonstrate that hafnium oxide (HfO2) thin films grown via atomic layer deposition on silicon pre-coated with aluminum (Al2O3) have etch resistance properties, which can be tuned simply by changing post-deposition annealing temperature. The etching rates hydrofluoric acid (HF) solutions were found to dependent temperature, rate decreasing...
Minimizing electrical losses at metal/silicon interfaces in high-efficiency single-junction silicon solar cells requires the use of carrier-selective passivating contacts. The electronic barrier heights insulator/silicon interface are necessary for calculating probability quantum tunneling charge carriers these interfaces. Thus, precise knowledge parameters is crucial development contact schemes. Using a photoemission-based method, we experimentally determine band offsets Al <sub...
Production of a temporally stable chemically enhanced ultra-thin HfO 2 interlayer with excellent passivation for use in photovoltaic passivating contacts.
Photoexcited muon spin spectroscopy (photo-μSR) is used to study excess charge carrier lifetimes in silicon. Experiments are performed on silicon wafers with very high bulk the surface passivation conditions intentionally modified control effective lifetime. When lifetime low (&lt;500 μs), implanting muons different depths enables reliable measurement of as a function distance from surface. It also demonstrated that photo-μSR technique can measure completed commercial gallium doped...
The recombination of photogenerated charge carriers at metal-semiconductor interfaces remains a major source efficiency loss in photovoltaic cells. Here, we present SiN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> and AlO nanolayers as promising interface dielectrics to enable high hole selective passivating contacts. It is demonstrated that deposited via direct plasma enhanced chemical vapour deposition can be grown controllably...
For a diverse range of semiconductor devices, the charge carrier lifetime is an essential characteristic. However, difficult to control, as it usually determined by variety recombination processes. indirect bandgap materials, well known that effective lifetimes can be improved passivating surface, effectively extinguishing surface-related for some applications, such photomodulators sub-infrared radiation, beneficial tailor specific values, in this particular case trading off between...