Enhanced stimulated emission of excited states in quantum wells by resonant tunneling

The electroluminescence properties of several resonant tunneling single quantum well structures are investigated that determine the feasibility of selective injection of carriers into a higher lying subbands. Lasing is observed via higher lying subbands rather than the ground state in 1 mm long lasers. It is demonstrated that in each of the proposed structures in this study both QW excited states and GaAs band to band transitions lase nearly simultaneously with a threshold current between 160 and 170 mA

Temperature characteristics of GaAsP/AlGaAs tensile strained quantum well lasers

The temperature characteristics of tensile strained GaAs1-yPy-Al0.35Ga0.65As single quantum well heterostructure (SQWH) laser diodes were studied. The dependence of the characteristics temperature (TO) on the quantum well composition in broad-area stripe lasers with identical quantum well widths (115 angstroms) and cavity lengths (750 μm) was examined. Laser diodes with seven different quantum well compositions ranging from y = 0 to y = 0.155 were examined. Results show that the highest characteristics temperatures occur not at the lattice-match composition y = 0 but for slightly tensile strained wells with y = 0.025 and y = 0.05. A strained layer laser model was employed to explain this qualitative behavior

Tensile-strained AlGaAs/GaAsP single quantum-well lasers

Experimental and theoretical results on OMVPE grown Al0.34Ga0.66As/GaAs1-yPy separate-confinement single quantum-well laser diodes are reported. CW output power as high as 620 mW/facet and pulsed threshold current densities (Jth) as low as 170 A/cm2 have been obtained from 90 × 1000 μm devices

Wide-bandwidth electron bolometric mixers. A 2DEG prototype and potential for low-noise THz receivers

This paper presents a new type of electron bolometric ('hot electron') mixer. We have demonstrated a three order of magnitude improvement in the bandwidth compared with previously known types of electron bolometric mixers, by using the two-dimensional electron gas (2DEG) medium at the hetero-interface between AlGaAs and GaAs. We have tested both in-house MOCVD-grown material, and MBE material, with similar results. The conversion loss (Lc) at 94 GHz is presently 18 dB for a mixer operating at 20 K, and calculations indicate that Lc can be decreased to about 10 dB in future devices. Calculated and measured curves of Lc versus PLO, and IOC, respectively, agree well. We argue that there are several different configurations of electron bolometric mixers, which will all show wide bandwidth, and that these devices are likely to become important as low-noise THz receivers in the future