Terahertz GaAs/AlAs quantum-cascade lasers

Journal Article · Mon Mar 07 00:00:00 EST 2016 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4943657· OSTI ID:22591410

Lü, X.; Rozas, G.; Biermann, K.; Grahn, H. T. ^[1]

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1. Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5–7, 10117 Berlin (Germany)

We have realized GaAs/AlAs quantum-cascade lasers operating at 4.75 THz exhibiting more than three times higher wall plug efficiencies than GaAs/Al{sub 0.25}Ga{sub 0.75}As lasers with an almost identical design. At the same time, the threshold current density at 10 K is reduced from about 350 A/cm{sup 2} for the GaAs/Al{sub 0.25}Ga{sub 0.75}As laser to about 120 A/cm{sup 2} for the GaAs/AlAs laser. Substituting AlAs for Al{sub 0.25}Ga{sub 0.75}As barriers leads to a larger energy separation between the subbands reducing the probability for leakage currents through parasitic states and for reabsorption of the laser light. The higher barriers allow for a shift of the quasi-continuum of states to much higher energies. The use of a binary barrier material may also reduce detrimental effects due to the expected composition fluctuations in ternary alloys.

• OSTI ID: 22591410
• Journal Information: Applied Physics Letters, Vol. 108, Issue 10; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALUMINIUM ARSENIDES
CURRENT DENSITY
DIFFUSION BARRIERS
EFFICIENCY
GALLIUM ARSENIDES
LASERS
LEAKAGE CURRENT
LEAKS
PROBABILITY
TERNARY ALLOY SYSTEMS
THRESHOLD CURRENT
VISIBLE RADIATION
WALLS