Gallium Nitride Applications

By Charles Martinez 2008

Gallium nitride (GaN) is a semiconductor that possesses unique characteristics that make it advantageous for the creation of efficient optoelectronic devices in addition to high power and high temperature applications. These devices should find wide practical applications in commercial markets and also in defence. The Inspec Database covers many of these emerging technologies. Potential and current uses of nitride technology along with their relevant Inspec classification codes, are as follows:

1) GaN could be used potentially for large TV screens or smaller full colour panels in trains or buses. Full colour displays were not possible because blue and green LED’s were not bright enough. GaN based LED’s are much more efficient and therefore provide another possibility for blue and green LED’s.

 

B4260DLight emitting diodes
B7260Display technology

 

2) LED’s consume less c and last longer therefore bolstering energy and cost saving. Nitride based semiconductors (emitting in the UV) can also be combined with phosphor converters in order to generate white light. This is unfortunately not yet possible due to the price factor in the manufacture of LED’s. Higher power output, even with higher efficiency, presents significant challenges to manage the heat generated by LED’s, since excess heat rapidly degrades the life of the LED. 

This has warranted the development of alternative approaches to manufacture LED’s in order to offer reduction of LED power consumption, improved thermal management, and more cost-efficient and reliable LED lighting systems, enabling LED’s to realise their full potential.

 

B4220MPhosphors
B4260DLight emitting diodes

 

3) Room temperature gallium nitride based lasers with impressive lifetimes have already been demonstrated. There is a significant market for optical reading and writing of data in CD, DVD and opto-magnetic memories.

 

A4255PLasing action in semiconductors
B4160Magneto-optical devices
B4210Optical storage and retrieval
B4320JSemiconductor lasers

 

4) Microwave amplifiers for wireless communications systems that translate into better reception on mobile phones and fewer low-earth satellites and transmitting stations in the environment. The greater transmitting power and higher efficiencies supplied by GaN materials means that fewer geostationary satellites will do the same job as many more low-earth satellites.

 

B1220Amplifiers
B1350FSolid-state microwave circuits and devices
B1350HMicrowave integrated circuits
B6250Radio links and equipment

 

5) Aerospace components that can operate over a wide temperature range and remain unaffected by radiation. Due to GaN’s chemical composition it is widely expected that the material will exhibit greater radiation hardness.

 

B2550RRadiation effects on semiconductor devices
B7600Aerospace facilities and techniques
E3650CAerospace industry

 

Despite GaN’s viable technological applications, some of the basic material properties of the group III nitride materials are not fully understood. Whilst extrinsic effects mentioned above can be improved by better growth and fabrication methods, the basic properties cannot currently be controlled; therefore the role which they play in device operations must be further studied. Although transport measurements and optical characterisation have gone some way to understanding these issues, there are still areas that need investigation. Inspec classification covers the main nitride semiconductor research topics:

 

A7220Electrical conductivity phenomena in semiconductors and insulators
A7280EElectrical conductivity of II-VI and III-V semiconductors
A7360LElectrical properties of II-VI and III-V semiconductors (thin films/low dimensional structures)
A7830GInfrared and Raman spectra in inorganic crystals
A7840GVisible and ultraviolet spectra -of II-VI and III-V semiconductors
 A7855EPhotoluminessence in II-VI and III-V semiconductors
A7865KOptical properties of II-VI and III-V semiconductors (thin films/low dimensional structures)
B2520DII-VI and III-V semiconductors