Electrically pumped blue laser diodes with nanoporous bottom cladding

TL;DR

This paper presents the development of electrically pumped blue laser diodes with nanoporous bottom cladding, demonstrating improved design and modeling for better optical confinement and device performance.

Contribution

It introduces a novel nanoporous bottom cladding in III-nitride laser diodes, combining experimental fabrication with theoretical modeling to optimize device performance.

Findings

Achieved laser emission at 448.7 nm with a slope efficiency of 0.2 W/A

Compared nanoporous cladding devices with reference structures, showing differences in lasing wavelength and efficiency

Theoretical modeling guided the optimal porosity and thickness for improved optical confinement.

Abstract

We demonstrate electrically pumped III-nitride edge-emitting laser diodes (LDs) with nanoporous bottom cladding. The LD structure was grown by plasma-assisted molecular beam epitaxy. Highly doped 350 nm thick GaN:Si cladding layer with Si concentration of 6 x 1019 cm-3 was electrochemically etched to obtain porosity of 15 +/- 3% with pore size of 20 +/- 9 nm. The devices with nanoporous bottom cladding are compared to the refer-ence structures. The pulse mode operation was obtained at 448.7 nm with a slope efficiency (SE) of 0.2 W/A while the reference device without etched cladding layer was lasing at 457 nm with SE of 0.56 W/A. The de-sign of the LDs with porous bottom cladding was modelled theoretically. Performed calculations allowed to choose the optimum porosity and thickness of the cladding needed for the desired optical mode confinement and reduced the risk of light leakage to the substrate and to the top-metal contact. This demonstration opens new possibilities for the fabrication of III-nitride LDs.