Deep-UV Light-Emitting Based on the hBN:S/hBN: Mg Homojunction

Area of Science:

• Materials Science
• Condensed Matter Physics
• Semiconductor Physics

Background:

• Hexagonal boron nitride (hBN) is a promising material for deep-ultraviolet (deep-UV) emitters.
• Achieving n-type conductivity in hBN is a significant challenge hindering device fabrication.

Purpose of the Study:

• To achieve n-type conductivity in hBN by doping with sulfur.
• To investigate the structural and electrical properties of sulfur-doped hBN (hBN:S).
• To demonstrate the potential of hBN:S for deep-UV emitter applications.

Main Methods:

• Density functional theory (DFT) calculations to study electronic properties.
• Experimental growth of multilayer hBN:S on sapphire substrates.
• Electrical characterization using different metal contacts (Ti and Ni).

Main Results:

• DFT calculations revealed shallow donor energy levels due to S 3p and B 2p orbital coupling.
• Multilayer hBN:S exhibited enhanced electron delocalization compared to monolayer.
• Experimentally grown hBN:S films showed measurable in-plane current.
• The sulfur-induced donor level was found at 0.349 eV below the conduction band minimum.

Conclusions:

• Sulfur doping is an effective method for achieving n-type conductivity in hBN.
• Multilayer hBN:S is more suitable for n-type conduction than monolayer hBN:S.
• A vertically-stacked n-hBN/p-hBN junction was successfully fabricated, showing promise for deep-UV emitters.