Influence of the quality of the heterointerface on the cyclotron resonance spectra of InAs/(AlGa)Sb heterostructures

Cyclotron resonance is measured in solitary type-II InAs-AlGaSb quantum wells grown by molecular-beam epitaxy under various growth conditions. Quantum oscillations observed in the cyclotron resonance spectra in InAs-GaSb samples are attributed to scattering by a short-range potential due to roughness of the heterointerface. A new method based on measurement of the cyclotron resonance spectra is proposed for assessing the quality of the heterointerface. Fiz. Tekh. Poluprovodn. 31, 1246–1248 (October 1997)     

Absorption and single-pass gain measurements in optically pumped type-II midinfrared laser structures

A single-pass method was employed to measure the gain and absorption in optically pumped midinfrared type-II semiconductor lasers. The technique requires minimal sample processing and allows a single sample to be used for both absorption and gain measurements. The gain measurements confirm previous observations that the differential gain of these structures drops off rapidly with increasing temperature. A comparison of absorption in samples with differing waveguide designs was used to estimate the effective index step between the core and cladding.     

Submillimeter photoconductivity of two-dimensional electron structures in Corbino geometry

The photoconductivity of a two-dimensional electron gas in the far IR range in a quantizing magnetic field is investigated for samples in Corbino geometry, which eliminates transport by edge states. It is shown that the photoelectric effect is more than simply the bolometric response of the system, acquiring a component induced by the direct involvement of photoexcited carriers in low-energy scattering processes. Fiz. Tekh. Poluprovodn. 33, 976–978 (August 1999)     

Population inversion in two-dimensional InAs/GaSb/AlSb systems

We analyse the potentiality of InAs/GaSb/AlSb tunnel structures for creation of the population inversion and stimulated radiation both in the presence and in the absence of magnetic field.     

High-Speed Stark Wavelength Tuning of MidIR Interband Cascade Lasers

Stark modulation of the wavelength of a midinfrared tunable interband cascade laser was studied. Wavelength modulation at frequencies exceeding 1 GHz was demonstrated. Estimates of capacitances inherent to the laser's structure suggested that improved packaging techniques could lead to modulation frequencies approaching 6 GHz     

Measurement of Semiconductor Laser Gain by the Segmented Contact Method Under Strong Current Spreading Conditions

A segmented contact method for the measurement of optical gain is developed for the case of strong current spreading. A simple model of current spreading in a ridge laser with a segmented contact is proposed and analyzed. We show that current spreading effects should be taken into account in lasers with low threshold current densities and high ldquoopeningrdquo voltages. When applied to interband cascade lasers, the method gives an internal optical loss of ~ 10-17 cm^-1 and a differential gain of ~ 2.9 cm/A at 80 K, which agrees well with previously reported Hakki-Paoli data. The limitations of the technique are discussed.     

GaSb-Based Mid-Infrared Single Lateral Mode Lasers Fabricated by Selective Wet Etching Technique with an Etch Stop Layer

We have demonstrated a wet etching technique for fabrication of narrow ridge lasers. Precise control over etching depth and ridge width was realized by introducing an etch stop layer into a laser structure and by using two etchants with different selectivity. The 6-μm-wide ridge laser emitting at 2 μm generated continuous-wave power of 70 mW at 20°C. Single lateral mode operation was observed up to 400 mA, corresponding to 8 × I _th.