What is LED?

1) In one sentence: What is an LED (Light Emitting Diode)?

An LED (Light Emitting Diode) is a tiny semiconductor electronic component that produces light when electricity flows through it.

To get the basics, you only need three words: electricity / light / semiconductor

2) An LED is not a “bulb”—it’s an electronic component

Many people think an LED is just another type of light bulb, but it works very differently.

• Incandescent bulb: Electricity heats a metal filament → it glows because of the heat

• LED: Electricity makes electrons move inside the semiconductor → light is produced during that process

👉 An LED doesn’t “burn” to make light.👉 It uses electron movement in a semiconductor to create light.

That’s why LEDs can be small, fast, and easy to control.

3) So what is an LED made of? (Core material)

The main body of an LED is made of semiconductor material.

What is a semiconductor?

A semiconductor is a material that is:

• not a perfect conductor (like metal),

• and not a perfect insulator (like plastic),

• but something in between—so we can precisely control how electricity flows.

Because of this property, engineers can design:

• where electrons go,

• how they move,

• and how much they move.

That’s the key to making light on purpose.

4) Most common LED material today: Gallium Nitride (GaN)

For modern LEDs used in streetlights, TVs, and phones, the most important material is usually:

👉 Gallium Nitride (GaN)

Why GaN is useful:

• It can produce high-energy light (blue light) efficiently

• It can be very bright even in a small size

• It is relatively strong against heat and voltage stress

That’s why GaN-based LEDs are used in:

• streetlights

• traffic lights

• car lighting

• indoor lighting

👉 GaN has become one of the core materials behind modern LEDs.

5) The real identity of “white LED” (important point)

Light color	Common semiconductor material
Red	Gallium Arsenide (GaAs)
Orange / Yellow	Gallium Phosphide (GaP)
Blue	Gallium Nitride (GaN)
White LED	Blue LED + phosphor

Here’s the surprising part:

A “white LED” is usually not a white LED chip.

It is basically a blue LED + phosphor.

How white light is made:

1. A GaN LED chip produces blue light

2. A phosphor layer is placed on top

3. Blue light hits the phosphor → the phosphor emits yellow-ish light

4. Blue + yellow mix → our eyes see it as white

So:

• the LED chip itself is blue

• the “white” is a mixed result

Because of this structure:

• the color temperature (K) can change

• the CRI (color rendering) can vary

• overall quality can differ depending on phosphor and design

6) Why does heat always matter with LEDs?

LEDs are efficient, but they still cannot convert 100% of electrical energy into light.

When electricity goes into an LED:

• some becomes light

• some becomes heat

If heat cannot escape well:

• brightness drops faster

• lifetime becomes shorter

• failures become more likely

That’s why in streetlights, it’s not only the LED chip that matters—👉 the thermal design (housing, heatsink) is just as important.

7) A more accurate “one-sentence” summary (now that you know the basics)

An LED is a tiny chip made from semiconductor materials (often GaN), and when electricity flows through it, electron movement produces light (and some heat).

Thank you for reading! See you later!