wave packet is the unit of wavelength of light.
wave packet is the unit of wavelength of light.
what is the unit of wavelength of light?
wave packet
Na
Na
the bandgap determines the wavelength at which leds can emit light and the wavelength at which photovoltaics operate most efficiently. wide-bandgap devices therefore are useful at shorter wavelengths than other semiconductor devices. the bandgap for gaas of 1.4 ev, for example, corresponds to a wavelength of approximately 890 nm, which is invisible infrared light (the equivalent wavelength for light energy can be determined by dividing the constant 1240 nm-ev by the energy in ev, so 1240 nm-ev/1.4 ev=886 nm). therefore, gaas photovoltaics are not ideal for converting shorter-wavelength visible light into electricity. silicon at 1.1 ev (1100 nm) is even worse. for solar-energy conversion using a single junction photovoltaic cell, the ideal bandgap has been variously estimated from around 1.0 ev up to around 1.5 ev (depending on various assumptions) because that low wavelength threshold covers nearly the entire solar spectrum that reaches the earth's surface, but a lower-bandgap single-junction cell wastes a large portion of that power by inefficiently converting the shorter-wavelength parts of the solar spectrum. because of this, a major area in solar energy research is developing multi-junction solar cells that collect separate parts of the spectrum with more efficiency, and wide bandgap photovoltaics are a key component for collecting the part of the spectrum beyond the infrared.
wide-bandgap semiconductor