Continuous-wave operation of nonpolar GaN-based vertical-cavity surface-emitting lasers

Charles A. Forman, Seunggeun Lee, Erin C. Young, Jared A. Kearns, Daniel A. Cohen, John T. Leonard, Tal Margalith, Steven P. DenBaars, Shuji Nakamura

Research output: Chapter in Book/Report/Conference proceedingConference contribution

6 Scopus citations


This is the first demonstration of continuous-wave (CW) operation of nonpolar GaN-based VCSELs. These devices had a dual-dielectric distributed Bragg reflector (DBR) design with ion implanted apertures and III-nitride tunnel junction (TJ) intracavity contacts. Unlike c-plane devices, nonpolar GaN-based VCSELs have anisotropic gain that leads to a 100% polarization ratio and polarization-locked VCSEL arrays. Previous nonpolar devices were unable to lase under CW operation, notably due to the thermally-insulating bottom dielectric DBR. Based on thermal modeling using COMSOL, the main thermal pathway was restricted to a thin p-side metal contact that goes around the bottom DBR to the submount. Heat flow was further impaired as the Au-Au thermocompression flip-chip bond created cracks and voids in the p-side metal. The thermal performance was improved in our latest VCSELs by increasing the cavity length to 23λ and utilizing Au-In solid liquid interdiffusion bonding to create a more robust pathway for heat transport. This led to stable CW VCSEL operation for over 20 minutes. The peak output powers for a 6 μm aperture VCSEL under CW and pulsed operation were 150 μW and 700 μW, respectively. Lasing wavelengths were observed at 406 nm, 412 nm, and 419 nm. The fundamental transverse mode was observed without the presence of filamentary lasing.
Original languageEnglish (US)
Title of host publicationGallium Nitride Materials and Devices XIII
ISBN (Print)9781510615496
StatePublished - Feb 23 2018
Externally publishedYes

Bibliographical note

KAUST Repository Item: Exported on 2022-06-28
Acknowledgements: This work was supported by the Solid State Lighting and Energy Electronics Center (SSLEEC) at UCSB and the KACST-KAUST-UCSB Solid State Lighting Program. The authors would like to acknowledge Mitsubishi Chemical Corporation for providing high-quality GaN substrates. Research carried out here made extensive use of shared experimental facilities including the Materials Research Laboratory: an NSF MRSEC, supported by NSF DMR 1121053, the UCSB Nanofabrication Facility, and the California NanoSystems Institute (CNSI) at UCSB.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.


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