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.

Biexcitons in GaAs quantum wells

Abstract: Careful examination of the exciton edge of the photoluminescence from a number of high-quality multiple-GaAs-quantum-well samples grown by molecular-beam epitaxy reveals at low temperatures a double peak whose splitting of approximately 1 meV decreases somewhat with increasing GaAs well width $L$. The higher-energy peak is due to the $n=1$ free-heavy-hole-exciton transition while the excitation intensity, temperature, and polarization dependences of the lower-energy peak suggest that it is due to biexcitons with a binding energy $B$ of about 1 meV. In support of the biexciton interpretation a theoretical calculation of $B(L)$ is presented. This calculation gives two-dimensional biexciton binding energies more than an order of magnitude larger than the three-dimensional calculated values.

A quantitative study of radiative, Auger, and defect related recombination processes in 1.3-/spl mu/m GaInNAs-based quantum-well lasers

Abstract: By measuring the spontaneous emission (SE) from normally operating /spl sim/1.3-/spl mu/m GaInNAs-GaAs-based lasers we have quantitatively determined the variation of each of the current paths present in the devices as a function of temperature from 130 K to 370 K. From the SE measurements we determine how the current I close to threshold, varies as a function of carrier density n, which enables us to separate out the main current paths corresponding to monomolecular (defect-related), radiative or Auger recombination. We find that defect-related recombination forms /spl sim/55% of the threshold current at room temperature (RT). At RT, radiative recombination accounts for /spl sim/20% of I/sub th/ with the remaining /spl sim/25% being due to nonradiative Auger recombination. Theoretical calculations of the threshold carrier, density as a function of temperature were also performed, using a ten-band k /spl middot/ p Hamiltonian. Together with the experimentally determined defect-related, radiative, and Auger currents we deduce the temperature variation of the respective recombination coefficients (A, B, and C). These are compared with theoretical calculations of the coefficients and good agreement is obtained. Our results suggest that by eliminating the dominant defect-related current path, the threshold current density of these GaInNAs-GaAs-based devices would be approximately halved at RT. Such devices could then have threshold current densities comparable with the best InGaAsP/InP-based lasers with the added advantages provided by the GaAs system that are important for vertical integration.

Stimulated emission from donor transitions in silicon

Abstract: Semiconductor sources of stimulated emission which are based on intraband optical transitions of highly nonequilibrium charge carriers are the object of an extensively developing field in physics. The new approaches in the development of unipolar active media are promising to bridge the wavelength range from l 1 m mu p to l 1000 mm of the electromagnetic spectrum. Examples of sources based on bulk material are germanium hot hole lasers [1] and Er-doped silicon lasers [2]. Emitters based on the properties of a two-dimensional electron gas in different kinds of heterostructures are quantum well “cascade” [3] and “fountain” lasers [4] as well as miniband Bloch oscillators in superlattices [5]. We propose a new far-infrared (FIR) (55 mm ,l,

Near-infrared semiconductor subwavelength-wire lasers

Abstract: We report near-infrared lasing in the telecommunications band in gallium antimonide semiconductor subwavelength wires. Our results open the possibility of the use of semiconductor subwavelength-wire lasers in future photonic integrated circuits for telecommunications applications.

Probing individual localization centers in an InGaN/GaN quantum well.

Abstract: Photoluminescence (PL) spectroscopy with subwavelength lateral resolution has been employed to probe individual localization centers in a thin InGaN/GaN quantum well. Spectrally narrow emission lines with a linewidth as small as 0.8 meV can be resolved, originating from the recombination of an electron-hole pair occupying a single localized state. Surprisingly, the individual emission lines show a pronounced blueshift when raising the temperature, while virtually no energy shift occurs for increasing excitation density. These findings are in remarkable contrast to the behavior usually found in macro-PL measurements and give a fundamental new insight into the recombination process in semiconductor nanostructures in the presence of localization and strong internal electric fields. We find clear indications for a biexciton state with a negative binding energy of about -5+/-0.7 meV.