University:
California State University, East Bay
Course:
CS 3590 | Data Communications and Networking
Academic year:

2023
Views:

368

Pages:

2
Author:

Jithin J I

NITRIDE-BASED HETEROSTRUCTURES FOR UV LASERS Introduction  III-nitride heterostructures enable UV lasers for sensing, medical, security apps  Lasers needed in UVA (320-400nm), UVB (280-320nm), UVC (<280nm) bands  AlGaN, InGaN, InAlGaN based quantum well structures being explored AlGaN MQW Lasers  Lasing demonstrated down to 241nm at room temperature  Threshold pumping power around 1200 kW/cm2  Gain around 120 cm-1 achieved in AlGaN/AlN MQWs Effect of Delta Layer Insertion  Inserting thin delta layers of GaN or AlGaN in QWs  Creates high carrier confinement and strain  Enhances UV emission intensity and optical gain  6-7x gain improvement reported with delta layers Optical Gain Optimization  Reducing QW width significantly boosts optical gain  Gain over 8000 cm-1 achieved in GaN/AlGaN with 40nm QW  High gain ~1700 cm-1 in 2nm thick AlGaN QW at 270nm Conclusion  Nitride heterostructures offer promising performance for UV lasers  Delta layers and QW engineering enable gain enhancement  Further advances needed towards electrically injected UV lasers Key Highlights  III-nitrides uniquely enable UV laser diodes  Intelligent heterostructure design is key for high gain  Thin delta layers dramatically improve carrier confinement  With optimized designs, high gain demonstrated down to 240nm  Essential progress towards on-chip UV sources for sensing applications