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Efficiency Statistics
The solar efficiency of crystalline silicon photovoltaic cells has been measured to rise above 25% in the lab. Multi-crystalline cells have tested higher than 20%, while polycrystalline silicon cells reached 18.1% efficiency.
Common Substrate Terms
- Silicon Photovoltaic
- Solar Cells
- Silicon Wafer
- SOI Wafers
- Cell Efficiency
- Amorphous Silicon
- Silicon Boules
What Types of Crystalline Silicon are There?
There are three primary forms of crystalline silicon: polycrystalline, monocrystalline, and PERL. All three are common semiconducting materials used in solar cells and photovoltaic technology. UniversityWafer, Inc. can supply substrates for all these applications.
Let's explore the differences between each of them. While they share a base element, their manufacturing processes, such as Czochralski growth or Float Zone methods, determine their final efficiency.
What are HOMO and LUMO?
Understanding the band gap is critical for semiconductor efficiency. The **HOMO** (Highest Occupied Molecular Orbital) and **LUMO** (Lowest Unoccupied Molecular Orbital) energy gap has important implications for studying kinetic stability and conductivity.
Currently, there are a number of approaches used to fabricate HOMO crystalline silicon solar cells. These include reduced processing steps, improved material quality, and passivating layers. HOMO crystalline silicon solar cells also exhibit improved contact resistivity thanks to the deposition of an ARC coating and texturing of the c-Si wafer.
The HOMO-LUMO energy gap determines excitation energy. For example, bulk c-Si is characterized by an indirect gap of 1.1 eV. This nature can be overcome through nanostructures which facilitate quantum confinement.
The Role of Czochralski Growth
The Czochralski-grown monocrystalline silicon (CZ-Si) remains the industry standard for high-efficiency electronics. This process often uses dopants like Gallium or Boron to tune electrical properties. For specific doping requirements, contact our engineering team.
What is PERL Technology?
PERL stands for "Passivated Emitter Rear Locally-diffused", and it combines the best features of PERT and PERC technologies. PERL solar cells combine elements from conventional solar cells to improve efficiency significantly.
In industrial PERL cells, p-type Si wafers are layered with an aluminum electro-reflector and screen-printed contacts. The rear side is passivated with silicon oxide or silicon nitride, and a back-surface field is created by laser-ablated openings in the rear dielectric stack. This minimizes shadowing losses and enhances total light coupling to the solar cell.
The inverted pyramid structure is the most effective texture for these cells. While random upright pyramids are easier to fabricate, regular arrays of inverted pyramids have achieved the highest efficiency in the world.
Monocrystalline Silicon Applications
Single-crystal silicon, or mono c-Si, is the base material for most modern electronics, including discrete components and integrated circuits. Its crystal-like structure and inherent stability make it a valuable component for electronic equipment.
Compared to other silicon varieties, it does not have grain boundaries, which allows charge carriers to flow more freely and prevent electron recombination. If you require Prime Grade Silicon Wafers for integrated circuits, UniversityWafer, Inc. offers a wide range of diameters and orientations.