Sensitivity of Heterointerfaces on Emission Wavelength in Quantum Cascade Lasers
Abstract
The measured emission wavelengths of A1InAs/GaInAs/InP quantum cascade lasers (QCLs) grown by metal organic vapor phase epitaxy (MOVPE) have been reported to be ~ 0.5 to1 m longer than the designed QCL wavelength. This work clarifies the origin of the red-shifted wavelength. It was found that A1InAs/GaInAs heterointerfaces are compositionally graded over ~ 2.5 to 4.5 nm, and indium accumulates at the A1InAs-to-GaInAs interface. Thus, the as-grown QCLs are far from the ideal abrupt interfaces used in QCL modeling. When graded layers are incorporated in QCL band structure and wave function calculations, the emission wavelengths are red shifted. Furthermore, we demonstrate that QCLs with graded interfaces can be designed without compromising performance and show greatly improved correlation between designed and measured emission wavelength. QCLs were designed for emission at 7.5 and 8.5 m. These QCLs exhibit room temperature peak power exceeding 900 mW and pulsed efficiencies of ~8.5 to 10%.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 18, 2016
- Accession Number
- AD1032984
Entities
People
- Austin J. Akey
- B. Schwarz
- Christine A. Wang
- D. Mcnulty
- D. R. Calawa
- Dominic F. Siriani
- F. Capasso
- J. P. Donnelly
- L. J. Missaggia
- M. C. Zheng
- Michael K. Connors
- T. S. Mansuripur
Organizations
- MIT Lincoln Laboratory