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Studies various InAs-on-AlSb interface structures grown by molecular beam epitaxy. Use of an atomic force microscope; Correlation between the interface configuration and the electron mobility in the InAs quantum well; Performance of transport measurements on the corresponding quantum well structures to establish the correlation between the interfacial morphology and the electron mobility in the channel.

We demonstrate the substantial suppression of infrared (IR) blackbody emission from HgCdTe photodiode arrays with cutoff wavelengths of 4.8, 5.5, and 6.0 μm. At room temperature, a reverse bias induces internal negative luminescence (NL) efficiencies of 95%, 93%, and 88%, respectively, which correspond to apparent cooling of the surface temperatures by 60, 59, and 49 K. Reverse-bias saturation current densities for the three devices were 0.11, 0.7, and 32 A/cm2. Measurement and analysis of the material transmission characteristics indicate that the small residual inefficiencies may be limited by a parasitic absorption process. The 4.8 and 5.5 pm photodiodes were fabricated into 18 × 2 arrays with total areas of 5 mm × 5 mm. In both cases, all 36 array elements were fully operable, and had similar electrical and NL properties. Effective fill factors were ≈100%, since carrier diffusion led to the extraction of carriers from regions between the elements. These results show that efficient, low-power NL devices with active areas in the square-inch range are now feasible for such applications as the cold shielding of infrared focal-plane arrays. [ABSTRACT FROM AUTHOR]

We investigate a Josephson field-effect transistor in which the electron gas in an InAs quantum well serves as the weak link between superconducting Nb electrodes. We modulate the density N[sub s], of electrons and the critical current I[sub c] in the weak link by applying a voltage to an insulated gate. Measurements of the dependence of I[sub c] on N[sub s], are in good agreement with a model in which each occupied subband of the InAs quantum well makes an independent contribution to I[sub c]. Inclusion of the nonparabolic band structure in InAs is crucial to this agreement. [ABSTRACT FROM AUTHOR]