Monolithic multiple colour emission from InGaN grown on patterned non-polar GaN

Area of Science:

• Materials Science
• Solid State Physics
• Optoelectronics

Background:

• Gallium nitride (GaN) based optoelectronics often face limitations due to the use of c-plane facets.
• Developing alternative facet structures is crucial for advancing III-nitride device performance.

Purpose of the Study:

• To develop a novel overgrowth approach for creating GaN structures with only non-polar and semi-polar facets.
• To eliminate the drawbacks associated with c-plane GaN in optoelectronic applications.
• To achieve multiple-color InGaN/GaN quantum wells (MQWs) for advanced optoelectronic devices.

Main Methods:

• Utilizing overgrowth on non-polar GaN micro-rod arrays on r-plane sapphire to form multiple-facet structures.
• Growing InGaN/GaN MQWs on these multiple-facet templates.
• Employing photoluminescence (PL) and cathodoluminescence (CL) measurements to characterize the optical properties.

Main Results:

• Successfully created multiple-facet GaN structures without c-plane facets.
• Achieved multiple-color InGaN/GaN MQWs due to varying indium incorporation efficiencies on different facets.
• Demonstrated tunable emission wavelengths and intensity ratios by controlling overgrowth conditions.
• Validated the approach through detailed optical measurements.

Conclusions:

• The novel overgrowth method effectively produces multi-facet GaN structures, enabling the growth of multi-color InGaN/GaN MQWs.
• This approach overcomes limitations of c-plane GaN and offers tunable optical properties.
• The technique shows significant potential for developing monolithic, phosphor-free white light-emitting diodes.