(Al, Ga)N-Based Quantum Dots Heterostructures on h-BN for UV-C Emission.

Area of Science:

• Materials Science
• Semiconductor Physics
• Optoelectronics

Background:

• Aluminium Gallium Nitride (AlGaN) quantum dots (QDs) are promising for deep-ultraviolet (DUV) applications.
• Achieving high-quality AlGaN QDs requires precise control over growth and material interfaces.
• Hexagonal boron nitride (h-BN) is explored as a buffer layer to improve AlGaN epitaxy.

Purpose of the Study:

• To investigate the growth of AlGaN QDs on hexagonal boron nitride (h-BN) buffer layers on c-sapphire.
• To optimize surface morphology and crystalline quality of AlGaN/AlN heterostructures.
• To characterize the optical emission properties of the fabricated AlGaN QDs.

Main Methods:

• Molecular beam epitaxy (MBE) for AlGaN QDs and AlN layers.
• Atomic force microscopy (AFM) for surface morphology analysis.
• X-ray diffraction (XRD) for crystalline quality assessment.
• Photoluminescence (PL) spectroscopy for emission properties and temperature dependence.

Main Results:

• Reduced surface roughness and improved morphology with thicker AlN layers (200 nm) on h-BN.
• Successful growth of AlGaN QDs embedded in AlGaN cladding layers.
• Deep-UV emission observed in the 275-280 nm range at room temperature.
• Limited emission intensity decrease with temperature, indicating good carrier confinement.

Conclusions:

• h-BN buffer layers facilitate the growth of high-quality AlGaN QDs on c-sapphire.
• The fabricated AlGaN QDs exhibit promising DUV emission and thermal stability.
• This approach is suitable for developing advanced DUV optoelectronic devices.