Composite GaN-C-Ga ("GaCN") Layers with Tunable Refractive Index

Area of Science:

• Materials Science
• Thin Film Technology
• Optical Materials

Background:

• Gallium Nitride (GaN) is a key material for optoelectronics.
• Carbonitrides offer tunable properties, but Gallium Carbon Nitride (GaCN) is underexplored.
• Novel composite thin films are needed for advanced optical applications.

Purpose of the Study:

• To synthesize and characterize novel Gallium Carbon Nitride (GaCN) composite thin films.
• To investigate the material's structure, composition, and optical properties.
• To explore GaCN as a prospective material for optical applications.

Main Methods:

• Alternating pulses of trimethylgallium (TMG) and ammonia (NH3) on silicon substrates.
• Mimicking atomic layer deposition (ALD) process conditions.
• Comprehensive material characterization including compositional and structural analysis.

Main Results:

• GaCN is a composite of nanoscale wurtzitic GaN polycrystals with carbon, nitrogen, and gallium inclusions.
• Tunable refractive index achieved by varying carbon content, increasing from 2.19 to 2.46 with 10 at.% carbon.
• Optical properties influenced by sp2-hybridized C=N clusters and interfacial carbon.

Conclusions:

• GaCN composite thin films are promising for optical applications due to tunable refractive indices.
• The composite structure, rather than a single phase, dictates the material's optical behavior.
• Understanding the formation pathways is crucial for optimizing GaCN for optoelectronic devices.