Articles you may be interested inThe effects of strain on intrasubband scattering rates in InPbased strainedlayer quantumwell lasers J. Appl. Phys. 76, 7399 (1994); 10.1063/1.357965Free carrier absorption in quantum well structures for polar optical phonon scattering
Sharp photoluminescence from the intra-4f shell of Er3+ is observed from erbium doped AlxGal-xAs (0 ≤x ≤ 1) grown by molecular beam epitaxy. The intensity of the luminescence from the erbium is strongly dependent on the aluminum composition with a maximum at x ≈ 0.6. We will present a model that explains the variation in intensity based on the energy transfer coupling efficiency between the host semiconductor and the optically active erbium ions. The coupling efficiency is dominated by the alignment or misalignment of the erbium energy levels with the energy bands of the host semiconductor and by the excess carrier lifetime in the host. The data and model, which are presented here for the first time, are consistent with our previous work on the effects of co-doping with Be or Si and with other workers' measurements of thermal quenching in rare earth doped semiconductors.
A compact monochromator has been designed to utilize recently developed free-standing XUV transmission gratings. Tests using a condensed spark source of far UV radiation show that this monochromator, with 20-microm slits, is capable of 0.08-nm resolution at 30 nm in the first order. A physical description of the system and test results are presented.
Data are presented demonstrating the operation of a current-injection laser diode with embedded reflectors instead of etched or cleaved facets. The laser structure, grown by molecular beam epitaxy, uses AlAs-GaAs superlattices SL’s in place of conventional AlxGa1−xAs cladding layers. The sample is patterned, etched, and Zn diffused to selectively disorder the SL cladding layers producing a ∼200×∼100 μm rectangular laser cavity embedded in the surrounding AlxGa1−xAs. Following Si3N4 deposition and metallization, the diodes are cut (not cleaved) with intentionally damaged edges. These devices operate as lasers (77 K, pulsed operation) with a mode spacing corresponding to either the ∼100-μm or the ∼200-μm cavity length formed by the selective interdiffusion of the SL cladding layer. This embedded-mirror laser structure may be useful in the development of optical integrated circuits by allowing semiconductor lasers to be monolithically integrated with other optical devices.
Some of the properties of InxGa1−xAs-GaAs strained-layer quantum-well-heterostructure (SL-QWH) injection lasers are described. The laser structures are grown by molecular beam epitaxy on n+ GaAs substrates. Following the growth of a 0.5-μm n+ GaAs buffer layer, a 2-μm Al0.45Ga0.55As n-type cladding layer is grown. Next an undoped active region is grown, consisting of ∼1600 Å of GaAs with three ∼40-Å In0.35Ga0.65As quantum wells separated by two ∼30-Å GaAs barrier layers. Following the active region, a 2-μm Al0.45Ga0.65As p-type cladding layer and a 0.5-μm p+ GaAs cap layer are grown. Broad-area SL-QWH lasers operate under pulsed conditions at room temperature with threshold current densities as low as 465 A/cm2. The operating wavelength is near 1 μm. Lasers have operated for up to 1000 h with less than 25% increase in current density to maintain a constant output of 2 mW/facet. Data are also presented describing the temperature dependence of threshold current density. Values of T0 between 80 and 103 K are observed near room temperature, indicating that these SL-QWH lasers are somewhat more sensitive to temperature changes than conventional laser structures.
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