Optically pumped GaN-AlGaN double-heterostructure lasers grown by ECR-GSMBE and HVPE
- Massachusetts Inst. of Tech., Lexington, MA (United States). Lincoln Lab.
The authors have observed laser emission with well-defined cavity modes in optically pumped GaN-Al{sub 0.1}Ga{sub 0.9}N double-heterostructure (DH) lasers. The laser structures were grown using an electron-cyclotron-resonance nitrogen-discharge source and gas-source molecular beam epitaxy (ECR-GSMBE) on thick ({ge} 10 {micro}m) GaN buffers grown by hydride vapor-phase epitaxy (HVPE) on c-plane sapphire. Transversely pumped cavities using a 337.1 nm nitrogen laser pump source exhibit a threshold pump fluence ranging from 0.15 to 0.3 mJ/cm{sup 2} at 77 K, a linear light output above threshold, a lasing wavelength of 358 nm, and an estimated differential quantum efficiency of 1%. The room-temperature threshold is about 1.7 times higher. Longitudinal mode structure has been resolved in a shorter-cavity (23 {micro}m) device at 77 K. The measured mode spacing of 0.56 nm corresponds to a group index of 5.0. Far-field measurements in a plane perpendicular to the plane of the heterostructure indicate a double-lobed pattern for a 1,000 {angstrom} thick GaN active region, and a single lobe with a FWHM of 60{degree} for a 4,000 {angstrom} active region. The thick HVPE GaN buffer layer provides for a lattice-matched growth and results in improved nucleation in MBE, as indicated by a high-quality reflection-electron-diffraction pattern of the as-loaded wafers. The surface morphology of the MBE layers on the HVPE buffer shows improved optical smoothness as compared to layers grown directly on sapphire using a low-temperature, MBE-grown GaN buffer. Laser facets were formed either by saw cutting or cleaving of the GaN buffer and epilayer along crystal planes. Details of the material development and laser performance are described.
- OSTI ID:
- 395048
- Report Number(s):
- CONF-951155-; ISBN 1-55899-298-7; TRN: IM9648%%125
- Resource Relation:
- Conference: Fall meeting of the Materials Research Society (MRS), Boston, MA (United States), 27 Nov - 1 Dec 1995; Other Information: PBD: 1996; Related Information: Is Part Of Gallium nitride and related materials; Ponce, F.A. [ed.] [Xerox Palo Alto Research Center, CA (United States)]; Dupuis, R.D. [ed.] [Univ. of Texas, Austin, TX (United States)]; Nakamura, S. [ed.] [Nichia Chemical Industries, Tokushima (Japan)]; Edmond, J.A. [ed.] [Cree Research, Inc., Durham, NC (United States)]; PB: 993 p.; Materials Research Society symposium proceedings, Volume 395
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
42 ENGINEERING NOT INCLUDED IN OTHER CATEGORIES
COMPOSITE MATERIALS
ENERGY BEAM DEPOSITION
MORPHOLOGY
PHOTOLUMINESCENCE
GALLIUM NITRIDES
ALUMINIUM NITRIDES
SEMICONDUCTOR LASERS
SEMICONDUCTOR MATERIALS
VAPOR PHASE EPITAXY
SAPPHIRE
MOLECULAR BEAM EPITAXY
ELECTRON CYCLOTRON-RESONANCE
ELECTRON DIFFRACTION
ELECTRON MOBILITY
SCANNING ELECTRON MICROSCOPY
LASER RADIATION
EMISSION SPECTRA