What Bandgap Energy Range is Required for Blue LEDs?

AI Thread Summary
Blue light wavelengths range from approximately 450 to 495 nm, which corresponds to a bandgap energy range of about 2.5 to 2.75 eV for semiconductors used in blue LEDs. The energy of light is calculated using the equation E = h * f, where h is Planck's constant and f is frequency, derived from the speed of light divided by wavelength. A common semiconductor that falls within this bandgap range is Gallium Nitride (GaN), which is widely used in blue LED technology. Understanding the relationship between wavelength and energy is crucial for selecting appropriate materials for LED applications. This knowledge is essential for anyone working with or studying semiconductor physics and optoelectronics.
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Homework Statement



Blue light corresponds to free space wavelengths of approximately 450 to 495 nm. If we want to use a semiconductor to make a blue LED, what range of energies must the semiconductor's bandgap fall within? Express your answer in units of electron volts(eV). What is an example of a real semiconductor with a bandgap in this range?


Homework Equations



?

The Attempt at a Solution




Can someone lead me in the right direction? From what I've read, blue light LED are high energy and the whole notion of bandgap energies confuses me.
 
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Relevant Equations..

Frequency = velocity * wavelength
Energy = Planck const * frequency
 
CWatters said:
Relevant Equations..

Frequency = velocity * wavelength

Frequency = speed / wavelength

ehild
 
Oops yes that's right.

Velocity = frequency * wavelength
so
frequency = Velocity/wavelength
 
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