In premium solid-state architectures requiring high color rendering indices, what unique structural method is used to construct a standard commercial white LED light bulb?
Depositing a yellow cerium-doped yttrium aluminum garnet phosphor coating directly over a blue indium gallium nitride semiconductor die
A standard commercial white LED is a phosphor-converted device: it starts from a single blue-emitting semiconductor die rather than mixing separate coloured diodes.
The blue die is made of indium gallium nitride (InGaN), an efficient direct-bandgap emitter of short-wavelength blue light.
Over this die a yellow phosphor — cerium-doped yttrium aluminium garnet (YAG:Ce) — is coated; it absorbs part of the blue light and re-emits broadband yellow light.
The un-absorbed blue and the re-emitted yellow combine to appear white to the eye, which is how a good colour rendering index is achieved from one chip.
The other options describe filament, gas-discharge or multi-diode schemes that are not how a commercial white LED bulb is built.
Hence, the answer is Depositing a yellow cerium-doped yttrium aluminum garnet phosphor coating directly over a blue indium gallium nitride semiconductor die.
Similar Questions
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When building a basic 6 by 4 LED matrix display, what is the total number of individual LEDs required to complete the grid?
Important Questions from LED Lights
Which of the following elements is NOT suitable for the fabrication of a light emitting diode structure?
A PN junction diode that ____ when activated is called a/an _______.
The IR LED sends out light with wavelengths ________ visible light.
LED is a _______ junction diode that emits light when activated.
Which one of the following LED emits an invisible light?
