Low-temperature growth of crystalline GaN films using energetic neutral atomic-beam lithography/epitaxy
Schematic of GaN thin film growth using energetic neutral atomic-beam lithography/epitaxy showing the energetic atom-beam source coupled to the group III-nitride thin-film growth system.
Recent work by Chemistry Division researchers on the low-temperature growth of crystalline GaN films was featured in the online edition of the journal Applied Physics Letters (Applied Physics Letters, 23 January 2006, Volume 88, Issue 4. Read the full paper)
Gallium nitride and related group III metal nitride thin film materials have become central components in high-power and opto-electronic devices such as blue LEDs and laser diodes, high-density optical data storage, flat panel displays, and solid state lighting. Current methods for growing GaN-related materials employ high temperatures and harsh, reactive environments. These conditions limit the range of substrates that can be used for fabricating devices, cause problems with dopant and metal segregation, prevent these materials from performing at optimum efficiency as green or red light emitters, and restrict their applications in other related technologies. LANL scientists have developed a new technique for growing crystalline and polycrystalline gallium nitride films on bare c-axis-oriented sapphire at low temperatures, 100 C to 500 C, using energetic neutral atom-beam lithography/epitaxy. Surface chemistry is activated by exposing substrates to nitrogen atoms with kinetic energies between 0.5 and 5.0 eV and a simultaneous flux of Ga metal, allowing low-temperature growth of GaN thin films. The as-grown GaN films show semiconducting properties, a high degree of crystallinity, and excellent epitaxial alignment. This method of low-temperature nitride film growth opens opportunities for integrating novel substrate materials with group III nitride technologies.
Contacts: Alex Mueller, and Mark Hoffbauer
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