What are the properties of amorphous silicon?

Amorphous Silicon Properties (Theoretical)

What is amorphous silicon carbide?

1. Introduction. Silicon carbide (SiC) in its amorphous and crystalline form is a promising wide band gap material for applications in the field of optoelectronics and microelectronics. Amorphous silicon carbide (a-SiC) has found a growing interest due to the potential applications for the optoelectronic devices.

What is the energy bandgap of amorphous silicon and crystalline silicon?

Amorphous silicon (a-Si) becomes a direct-gap semiconductor with an band gap of about 1.75 eV. Absorption is higher in a-Si compared to crystal silicon (c-Si), but p-i-n structures are generally still used.

Is Silicon an amorphous solid?

amorphous semiconductor solids, such as amorphous silicon (a-Si) and amorphous germanium (a-Ge).

Why is amorphous silicon used?

Amorphous silicon (a-Si) is the non-crystalline form of silicon used for solar cells and thin-film transistors in LCDs. Used as semiconductor material for a-Si solar cells, or thin-film silicon solar cells, it is deposited in thin films onto a variety of flexible substrates, such as glass, metal and plastic.

Does amorphous silicon burn in air?

When amorphous silicon is heated in air, it oxidizes at the surface level & catches fire. What happens when silicon is burnt in air? Silicon burns brilliantly in air and vigorously in oxygen to form silicon dioxide. It is an exothermic reaction.

What is amorphous silicon used for?

Amorphous silicon alloy films are valuable as the active layers in thin-film photovoltaic cells, two-dimensional optical position detectors, linear image sensors (optical scanners), and thin-film transistors used in liquid crystal display panels.

How amorphous silicon is formed?

Amorphous silicon thin films were first deposited by plasma-enhanced chemical vapor deposition (PECVD). The amorphous silicon layers deposited from silane by PECVD could be doped by adding to the plasma discharge either phosphine to form n-type layers, or diborane to form p-type layers.

Are obtained from the purest form of silicon?

Quartz
Quartz is the crystalline form of Silica and hence is the purest form of Silica.

How amorphous silicon is manufactured?

The manufacture of amorphous silicon photovoltaic cells is based on plasma-enhanced chemical vapor deposition (PECVD), which can be used to produce silicon thin film. Substrate can be made of the flexible and inexpensive material in larger sizes, for example stainless steel or plastic materials.

Why is SiO2 not SiO4?

The formula for silica is very simple—SiO2. The silica structures (and those of metal silicates) have only SiO4 tetrahedra, and the 1:2 ratio of SiO2 requires that each oxygen atom is shared by two tetrahedra in silica. Liquid silica does not readily crystallize but solidifies to a glass.

How is hydrogenated amorphous silicon grown for large scale manufacturing?

Only a thin film (less than 1 μm) is needed to absorb the sunlight rather than hundreds of micrometer (μm) that is needed for a conventional cell. The material cost is thus low. The film is grown using a plasma deposition process at a pressure of about 1 Torr and temperatures below 300 °C making it viable for large-scale manufacturing.

How is the defect density of amorphous silicon reduced?

Incorporation of hydrogen reduces the defect density, and thus the material is in fact an alloy of amorphous silicon and hydrogen, and is referred to as hydrogenated amorphous silicon or amorphous silicon alloy. In spite of many advances made, the defect density is still much larger than that in crystalline silicon.

How are hydrogenated amorphous silicon-sulfur alloy layers prepared?

Hydrogenated amorphous silicon-sulfur alloy layers were prepared by the RF glow discharge decomposition of a mixture of SiH4 and H 2 S gases diluted in helium. Films were concurrently deposited on Corning 7059 glass and on highly resistive c-Si substrates. The substrate temperature during growth was held constant at 250°C.

How is amorphous silicon different from crystalline silicon?

An important distinction between amorphous and crystalline silicon is in the nature of the energy gap. Crystalline silicon exhibits an indirect band gap of about 1.1 eV, while a-Si:H has a direct band gap in the range 1.5–2.0 eV, depending on growth conditions and hydrogen content [86,87].