Title :
Intersubband gain and stimulated emission in long-wavelength (λ=13 μm) intersubband In(Ga)As-GaAs quantum-dot electroluminescent devices
Author :
Krishna, Sanjay ; Bhattacharya, P. ; Singh, J. ; Norris, T. ; Urayam, J. ; McCann, Patrick J. ; Namjou, Khosrow
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., Michigan Univ., Ann Arbor, MI, USA
fDate :
8/1/2001 12:00:00 AM
Abstract :
The dynamics of injected carriers and the conditions for intersubband gain and population inversion in In(Ga)As-GaAs self-organized quantum dots have been studied. Direct femtosecond pump-probe spectroscopy as a function of temperature and excitation density confirms earlier results and shows a long (>100 ps) electron relaxation time between the excited states and ground state in the dots. Intersubband gains as high as 170 cm-1 are calculated in the dots. Far-infrared spontaneous emission centered around 13 μm is observed in edge-emitting light-emitting diodes. Stimulated emission, with a distinct threshold around 1.1 kA/cm2 in the light-current characteristics, is observed in plasmon-enhanced waveguide devices. The intersubband threshold occurs after a threshold is observed for interband lasing (~1 μm) in the same device
Keywords :
III-V semiconductors; electron relaxation time; excited states; gallium arsenide; high-speed optical techniques; indium compounds; light emitting diodes; population inversion; quantum well devices; quantum well lasers; semiconductor quantum dots; spontaneous emission; stimulated emission; 100 ps; 13 mum; In(Ga)As-GaAs quantum-dot electroluminescent devices; InAs-GaAs; InGaAs-GaAs; direct femtosecond pump-probe spectroscopy; distinct threshold; edge-emitting light-emitting diodes; electron relaxation time; excitation density; excited states; far-infrared spontaneous emission; ground state; injected carrier dynamics; interband lasing; intersubband gain; intersubband threshold; light-current characteristics; long-wavelength; phonon bottleneck; plasmon-enhanced waveguide devices; population inversion; stimulated emission; Electroluminescent devices; Energy states; Hot carriers; Light scattering; Particle scattering; Quantum cascade lasers; Quantum dots; Quantum well lasers; Spectroscopy; Stimulated emission;
Journal_Title :
Quantum Electronics, IEEE Journal of
