Surface-bound field emission luminescence: The remarkable principle that makes semiconductors glow

LED lights have become indispensable in our daily lives—whether in smartphone screens, car headlights, or street lighting. Yet many are unaware that LED light actually originates from a physical phenomenon called surface-bound field emission.

So what is surface-bound field emission?

Simply put, it's a mechanism that utilizes the p-n junction within semiconductor materials to generate light. Common materials include gallium arsenide (GaAs) and gallium phosphide (GaP).

When current flows through a p-n junction, electrons and holes meet and recombine within the junction region. This recombination releases energy, which is emitted as photons—the source of light.

Why is it more efficient than conventional bulbs?

Traditional bulbs, like incandescent lamps, emit light by heating a filament—essentially thermal radiation. Surface-junction field emission is fundamentally different, as it doesn't rely on thermal energy. In other words, it doesn't need to heat materials to incandescence to produce light. This frees it from the thermodynamic constraints of Planckian radiation, theoretically enabling extremely high luminous efficiency.

From Laboratory to Everyday Life

Initially, this principle was merely a research phenomenon in semiconductor physics. Later, we discovered its stable light emission and low energy consumption, leading to the development of light-emitting diodes (LEDs).

Today, the various LED lights, indicator lights, and displays we use are all products of surface-bound field emission. It can be said that the discovery of this principle has fundamentally transformed the landscape of lighting and display technologies.