Quantum well

About: Quantum well is a research topic. Over the lifetime, 44627 publications have been published within this topic receiving 674023 citations. The topic is also known as: QW & quantum potential well.

Lasing at three-dimensionally quantum-confined sublevel of self-organized In/sub 0.5/Ga/sub 0.5/As quantum dots by current injection

Abstract: A laser oscillation from self-organized In/sub 0.5/Ga/sub 0.5/As quantum dots is achieved at 80 K by current injection. Lasing at a three-dimensionally quantum confined sublevel of the In/sub 0.5/Ga/sub 0.5/As quantum dots is clearly demonstrated for the first time by electroluminescence and diamagnetic energy shift measurement. The results predict the possibility of ultra-low threshold current operation of quantum dot lasers.

Carrier capture into a semiconductor quantum well.

Abstract: We experimentally observed an oscillating carrier capture time as a function of quantum well thickness. The capture times were obtained in a separate confinement quantum well structure by subpicosecond rise time measurements of the quantum well luminescence as well as by pump-probe correlation measurements of the population decay in the barrier layer. Both experimental techniques yield an oscillating capture time between 3 and 20 ps, in excellent agreement with the theoretical predictions. In a classical picture, our results correspond to a local capture time oscillating between 0.1 and 1.8 ps. Furthermore, the dependence of the capture time on the excitation energy is analyzed and the time-dependent position of the quasi-Fermi-level in the barrier layer is tracked experimentally. We find that the carrier capture time is very sensitive to the detailed structure parameters as well as to the carrier distribution in the barrier. Carrier capture is found to be an ambipolar process in which the oscillations of the observed capture times are due to the quantum-mechanical oscillation of the electron wave-function overlap above the well. Finally, electron capture is demonstrated to be dominated by LO-phonon emission.

Tunable infrared modulator and switch using Stark shift in step quantum wells

Abstract: A tunable infrared modulator and/or switch using intersubband Stark shift in a step quantum well is discussed. The device utilizes the intersubband absorption and the large change of separation between energy levels in the step quantum well under an applied electric field. The incident infrared beam on the device is either absorbed or transmitted depending on the energy separation of the levels, and thus the modulation can be achieved by adjusting the energy levels with an applied electric field. The extremely short lifetime of the intersubband transition makes this modulator suitable for application in high-speed long-wavelength optical communications. >

Coulomb memory signatures in the excitonic optical stark effect

Abstract: Differential absorption spectra of high-quality InGaAs quantum wells are presented for various pump detunings and polarization configurations. For low intensity pump pulses tuned well below the exciton a redshift is observed for opposite circularly polarized probe pulses. Microscopic calculations show that this redshift originates from memory effects in the Coulomb-induced excitonic correlations.