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Inhomogeneous Current Injection and Filamentary Lasing of Semipolar ( 20 21 ¯ ) Blue GaN‐Based Vertical‐Cavity Surface‐Emitting Lasers with Buried Tunnel Junctions
Author(s) -
Kearns Jared A.,
Back Joonho,
Palmquist Nathan C.,
Cohen Daniel A.,
DenBaars Steven P.,
Nakamura Shuji
Publication year - 2020
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201900718
Subject(s) - lasing threshold , aperture (computer memory) , materials science , optics , laser , optoelectronics , current (fluid) , current density , physics , quantum mechanics , acoustics , thermodynamics
Blue ( 20 21 ¯ ) semipolar vertical‐cavity surface‐emitting lasers with a buried tunnel junction current aperture are demonstrated under continuous‐wave operation with a differential efficiency of 4% and a threshold current of 2.7 mA for a lasing mode at 452 nm. The effects of the aperture diameter on these 9 λ cavity length devices are presented, showing that the differential efficiency increases with aperture size, whereas the threshold current density remains constant for apertures larger than 10 μm. Filamentary lasing is observed in the larger aperture sizes, and it is suggested that this mode behavior is due to current injection inhomogeneity across the aperture. This theory is supported by the correlation between optical nearfield images and thermal microscopy images.