1,811 research outputs found
Quantum wells with atomically smooth interfaces
By a cleaved-edge overgrowth method with molecular beam epitaxy and a (110)
growth-interrupt-anneal, we have fabricated a GaAs quantum well exactly 30
monolayers thick bounded by atomically smooth AlGaAs hetero-interfaces without
atomic roughness. Micro-photoluminescence imaging of this quantum well indeed
shows spatially uniform and spectrally sharp emission over areas of several
tens of m in extent. By adding a fractional GaAs monolayer to our quantum
well we are able to study the details of the atomic step-edge kinetics
responsible for flat interface formation.Comment: 4 pages, 3 figures, revTex
One-dimensional continuum and exciton states in quantum wires
High-quality T-shaped quantum wires are fabricated by cleaved-edge overgrowth
with the molecular beam epitaxy on the interface improved by a growth-interrupt
high-temperature anneal. Characterization by micro-photoluminescence (PL) and
PL excitation (PLE) spectroscopy at 5 K reveals high uniformity, a sharp
spectral width, and a small Stokes shift of one-dimensional (1-D) excitons. The
PLE spectrum for 1-D states shows a large peak of ground-state excitons and a
small absorption band ascribed to 1-D continuum states with an onset at 11 meV
above the exciton peak.Comment: 4 pages, 4 figures, RevTe
Lasing from a single quantum wire
A laser with an active volume consisting of only a single quantum wire in the
1-dimensional (1-D) ground state is demonstrated. The single wire is formed
quantum-mechanically at the T-intersection of a 14 nm Al_{0.07}Ga_{0.93}As
quantum well and a 6 nm GaAs quantum well, and is embedded in a 1-D single-mode
optical waveguide. We observe single-mode lasing from the quantum wire ground
state by optical pumping. The laser operates from 5 to 60 K, and has a low
threshold pumping power of 5 mW at 5 K.Comment: 4 pages including 4 figure
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