AMORPHOUS SILICON THIN FILM
This type of thin-film cell is mostly fabricated by a technique called plasma-enhanced chemical vapor deposition. It uses a gaseous mixture of silane and hydrogen to deposit a very thin layer of only 1 micrometre of silicon on a substrate, such as glass, plastic or metal, that has already been coated with a layer of transparent conducting oxide. Other methods used to deposit amorphous silicon on a substrate include sputtering and hot wire techniques.
a-Si is attractive as a solar cell material because it’s an abundant, non-toxic material. It requires a low processing temperature and enables a scaleable production upon a flexible, low-cost substrate with little silicon material required. Due to its bandgap of 1.7 eV, amorphous silicon also absorbes a very broad range of the light spectrum, that includes infrared and even some ultraviolet and performs very well at weak light. This allows the cell to generate power in the early morning, or late afternoon and on cloudy and rainy days, contrary to crystalline silicon cells, that are significantly less efficient when exposed at diffuse and indirect daylight.
However, the efficiency of an a-Si cell suffers a significant drop of about 10 to 30 percent during the first six months of operation. This is called the Staebler-Wronski effect a typical loss in electrical output due to changes in photoconductivity and dark conductivity caused by prolonged exposure to sunlight
amorphous silicon is the non-crystalline form of silicon and it can be deposited in thin films at low temperature on to variety of substrates for manufacturing amorphous silicon thin film solar panels. Because of using amorphous silicon and manufacturing process is quite easy makes it cheap compare to crystalline solar panels cost but this low price achieved at cost of less efficiency due to use of amorphous silicon. But their low cost per watt become attractive factor for wide use of thin film solar panels.
Amorphous silicon solar panel is made from non-crystalline, allotropic form of silicon and the most well-developed thin film technology then other thin film. Thin-film silicon is an alternative to conventional wafer crystalline silicon but still many miles to go for that. While chalcogenide-based CdTe and CIGS thin films have been developed in the lab with great success, there is still industry interest in silicon-based thin films because of toxicity and humidity issues with CdTe thin films and low manufacturing yields of CIGS due to material complexity. Due to Wronski effect and other losses amorphous silicon thin film lifespan ranges around 15 years. amorphous silicon thin film efficiency ranges around 10%.