Multi-junction GaAs cells single crystal is known as "noble semiconductor" because of its high price. It is reported that the price of GaAs single crystal is about 20 to 30 times that of silicon single crystal of the same size. Many people who want to buy multi-junction GaAs cells often balk at the price.
So, is multi-junction GaAs cells really worth that much? Let's have a look!
GaAs belongs to III-V compound semiconductor materials, and its energy gap is more suitable to match the solar spectrum, and it can withstand high temperature. Compared with silicon solar cells, multi-junction GaAs solar cells have better performance. As early as 1954, GaAs was found to have photovoltaic effect. In the 1970s, with the participation of major companies and research units, GaAs began to flourish as a solar cell.
The band gap of GaAs is wider than that of Si, and the spectral responsivity and space solar spectral matching ability of GaAs are better than that of Si. Therefore, the photoelectric conversion efficiency of multi-junction GaAs solar cells is high. It can be made into ultra thin cell.
The multi-junction GaAs solar cells Also absorb 95% of the sun's light, Si needs 150 μ Thickness above M, but GaAs only needs 5 μ m~10 μ m. The quality of solar cells made of GaAs can be greatly reduced.
Multi-junction GaAs solar cells have the advantages of flexible bending, light weight, adjustable color and plastic shape, which can maximize the sensitive area, so it can greatly improve the solar power generation.
Generally speaking, the current silicon photocell can not operate normally under the working environment of 200 ℃. Experimental data show that multi-junction GaAs solar cells can still work normally at 250 ℃.
The sensitivity of crystal silicon photovoltaic system to light is not very high. When the light is poor in rainy days, it can not work. multi-junction GaAs solar cells can generate electricity in weak light environment, but the efficiency of power generation is less than that of sufficient sunlight.
Gallium is scarce, arsenic is toxic, and its production mode is different from that of traditional silicon. Gallium arsenide needs to be made by epitaxial technology. The diameter of this type of epitaxial wafer is usually 4-6 inches, much smaller than that of silicon wafer 12 inches. The epitaxial wafer needs special machine, so the cost will be relatively high. If you want to know Is GaAs toxic, Is it Safe to Touch Gallium, pls click.
Solar cells are generally darker in color due to their technological reasons, which means that their thermal effects are more serious. Especially in the first few years of use, it shows a high-speed attenuation state, which can reach about 20%. Therefore, gallium arsenide battery needs to be cooled sufficiently to ensure its power generation efficiency and reduce heat attenuation.
Gallium arsenide is more brittle in physical properties than silicon, which makes it easier to break when it is processed. Therefore, it is usually used to make it into thin films and use substrate (GE) to combat its disadvantages in this respect, but also increases the complexity of technology.
Although gallium arsenide is required in technology and expensive than silicon, its superior performance makes the demand of gallium arsenide growing. In addition, the potential market and technology breakthrough of GaAs single crystal for satellite communication system and vehicle radar will be more widely used in the future.