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.

Band-structure engineering for low-threshold high-efficiency semiconductor lasers

Abstract: It is shown that by using a strained-layer superlattice to form the active region of a quantum-well laser the threshold current can be reduced and Auger recombination and inter-valence band absorption can be effectively eliminated. The band-structure requirements are discussed generally and might be achieved by alternative methods.

Effect of Quantum-Well Structures on the Thermoelectric Figure of Merit in the Si/Si1-xGex System

Abstract: The Si/Si1-xGex quantum well system is attractive for high temperature thermoelectric applications and for demonstration of proof-of-principle for enhanced thermoelectric figure of merit Z, since the interfaces and carrier densities can be well controlled in this system. We report theoretical calculations for Z in this system, based on which Si/Si1-xGex quantum-well structures were grown by molecular-beam epitaxy. Thermoelectric and other transport measurements were made, indicating that an increase in Z over bulk values is possible through quantum confinement effects in the Si/Si1-xGex quantum-well structures.

GaInNAs: a novel material for long-wavelength semiconductor lasers

Abstract: GaInNAs was proposed and created in 1995 by the authors. It can be grown pseudomorphically on a GaAs substrate and is a light-emitting material having a bandgap energy suitable for long-wavelength laser diodes (1.3-1.55 /spl mu/m and longer wavelengths). By combining GaInNAs with GaAs or other wide-gap materials that can be grown on a GaAs substrate, a type-I band lineup is achieved and, thus, very deep quantum wells can be fabricated, especially in the conduction band. Since the electron overflow from the wells to the barrier layers at high temperatures can he suppressed, the novel material of GaInNAs is very attractive to overcome the poor temperature characteristics of conventional long-wavelength laser diodes used for optical fiber communication systems. GaInNAs with excellent crystallinity was grown by gas-source molecular beam epitaxy in which a nitrogen radical was used as the nitrogen source. GaInNAs was applied in both edge-emitting and vertical-cavity surface-emitting lasers (VCSELs) in the long-wavelength range. In edge-emitting laser diodes, operation under room temperature continuous-wave (CW) conditions with record high temperature performance (T/sub 0/=126 K) was achieved. The optical and physical parameters, such as quantum efficiency and gain constant, are also systematically investigated to confirm the applicability of GaInNAs to laser diodes for optical fiber communications. In a VCSEL, successful lasing action was obtained under room-temperature (RT) CW conditions by photopumping with a low threshold pump intensity and a lasing wavelength of 1.22 /spl mu/m.

Stimulated emission in semiconductor quantum wire heterostructures.

Abstract: We report the first observation of stimulated emission in quasi-one-dimensional semiconductor quantum wires Amplified spontaneous emission and stimulated emission spectra of the GaAs/AlGaAs quantum wires exhibit fine structure arising from transitions between lateral, one-dimensional electron and hole subbands The observed subband separations, \ensuremath{\sim}10 meV, are consistent with the calculated ones

Nonequilibrium condensates and lasers without inversion: Exciton-polariton lasers

Abstract: We analyze elementary properties of exciton and polariton lasers --- devices that generate coherent optical and matter waves using final-state stimulation of exciton-phonon scattering. First we discuss the relation between the conditions for the onset of equilibrium and nonequilibrium excitonic condensates. Provided that the thermal de Broglie wavelength ${\ensuremath{\lambda}}_{\mathit{T}}$ exceeds the exciton Bohr radius ${\mathit{a}}_{\mathit{B}}$, an exciton laser operates without electronic population inversion. In contrast to previous proposals, this is a different type of laser without inversion which utilizes many-body coherences. When the excitonic character of the polariton branch vanishes, a polariton laser becomes indistinguishable from a photon laser. \textcopyright{} 1996 The American Physical Society.