Silicon bulk growth for solar cells: Science and technology

Abstract

The photovoltaic industry is in a phase of rapid expansion, growing by more than 30% per annum over the last few decades. Almost all commercial solar cells presently use single-crystalline or multicrystalline silicon wafers similar to those used in microelectronics; meanwhile, thin-film compounds and alloy solar cells are currently under development. The laboratory performance of these cells, at 26% solar energy conversion efficiency, is now approaching thermodynamic limits, with the challenge being to incorporate these improvements into low-cost commercial products. Improvements in the optical design of cells, particularly in their ability to trap weakly absorbed light, have also led to increasing interest in thin-film cells based on polycrystalline silicon; these cells have advantages over other thin-film photovoltaic candidates. This paper provides an overview of silicon-based solar cell research, especially the development of silicon wafers for solar cells, from the viewpoint of growing both singlecrystalline and multicrystalline wafers.

Powerful recombination centers resulting from reactions of hydrogen with carbon–oxygen defects in n‐type Czochralski‐grown silicon

“…The work reported here shows conclusively that the centers are related to carbon–oxygen–hydrogen complexes. So, as carbon is present as an impurity in some solar silicon materials including those grown by new methods under development commercially , our new findings suggest that this may be an important issue for future silicon PV technologies.…”

“…Our measurements indicate that under common manufacturing conditions the concentration of these recombination centers is sufficiently high to have an important effect on the minority carrier lifetime and, in consequence, on the efficiency of solar cells. The probability of this happening is large as carbon and oxygen are the main light element impurities in recent commercial Cz and C‐Cz solar silicon , and hydrogen is readily introduced during solar cell processing. The properties of the defects are identical whether the hydrogen is introduced from wet etching, hydrogenated silicon nitride, or from remote hydrogen plasma.…”

Growth Mechanism and Opto-Structural Characterization of Vertically Oriented Si Nanowires: Implications for Heterojunction Solar Cells

“…As yet, it is the most used semiconductor in electronic devices due to its natural abundance, low toxicity, and compatibility with large-scale device fabrication. 1,2 Si is omnipresent in the photovoltaic sector because it retains intense optical absorption over a wide range of the solar spectrum, involving its various narrow and wide band gap alloys. 3,4 Si-based solar cell technologies are categorized into two main branches with (i) bulk and (ii) thin-film configurations.…”

“…Silicon (Si) is the backbone of the modern semiconductor industry. As yet, it is the most used semiconductor in electronic devices due to its natural abundance, low toxicity, and compatibility with large-scale device fabrication. , Si is omnipresent in the photovoltaic sector because it retains intense optical absorption over a wide range of the solar spectrum, involving its various narrow and wide band gap alloys. , Si-based solar cell technologies are categorized into two main branches with (i) bulk and (ii) thin-film configurations. , In both areas, many technological advances have been made over the years around the globe. , However, one common concern of both technologies lies in the loss of incident solar light by reflection from the top surface of the device. Various single or multilayer antireflection coatings (ARCs) on the surface of conventional solar cells have been adopted in this context. , However, the fabrication of these ARCs requires various complex calculations on their graded refractive indices.…”

Radiation‐induced interstitial carbon atom in silicon: Effect of charge state on annealing characteristics

“…Carbon is an important technological impurity in silicon . In commercial Si crystals, carbon atoms are present in concentrations typically in the 10 15 to 10 16 cm −3 range and in as‐grown material are located mainly at substitutional (C s ) sites.…”