Light-emitting diodes visible spectrum

The application of modem epitaxial techniques (see Chapter 8) has led to a rapid improvement in the material quality of SiC and made practical SiC devices a reality. The applications of SiC include high-temperature, high-power devices, microwave devices (both avalanche diodes and field effect transistors), and optoelectronic devices, such as photodiodes and light-emitting diodes which emit throughout the visible spectrum into the ultraviolet. 

The light-emitting diode (LED) is a semiconductor device that emits incoherent, narrow-spectrum light. The color of the emitted light depends on the semiconducting material used, and can be near ultraviolet, visible, or infrared. 

The construction of light-emitting diodes (LEDs) is a very fast-growing field. Thiophene-based polymers are, among PHCs, the most promising materials employed for this purpose. LEDs have been produced from various blends of thiophene-based polymers in order to tune the color of the emitted light for complete covering of the visible spectrum [331]. 

Direct band-gap semiconductor nanostructures have great potential for nano-photonic devices, including solar cells, light emitting diodes, and photodetectors. CdSe is particularly interesting for photovoltaics, since its band-gap favors absorption over a wide range of the visible spectrum. 

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