Violet-emitting diode may operate at room temperature

Fabrication of a violet-emitting diode laser from gallium nitride (GaN) based wide-bandgap materials will be described by researchers from the Nagoya Institute of Technology (Nagoya, Japan) at the 41st annual IEEE International Electron Devices Meeting (Dec. 10-13, 1995, Washington, DC). The researchers' paper is the first to report pulsed stimulated emission at 300 K from a current-injected surface-emitting InGaN/AlGaN double-heterostructure diode whose active layer comprises InGaN co-doped with silicon and zinc.

At injection currents above 400 mA, the main emission wavelength is 380 nm, which originates from band-to-band emission in the InGaN layer. A weaker emission at 440 nm is attributed by the researchers to impurity in the same layer and saturates as the injected current increases above 800 mA.

Although stimulated emission from photopumped GaN devices has been reported at temperatures up to 425 K, only spontaneous emission has previously been observed at 300 K with current injection. The researchers hope their technique can be developed for diode-laser operation at room temperature.