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A study analyzed molecular beam epitaxy grown InAs/GaSb superlattices, containing InSb-like interfacial layers by a combination of x-ray diffraction and structural refinement. The combined SUPREX//XRD experiments reveal that the absence of certain odd order satellite features in the x-ray data is due to asymmetric and inhomogeneous lattice strain.

The temperature-dependent Hall effect and the Fourier transform photoconductivity (FTPC) were used to study deep levels between .1 and 1 electron volts in semi-insulating and high resistivity undoped horizontal Bridgman gallium arsenide. FTPC was effective in studying deep levels, identifying photoionization thresholds at .44, .8 and 1 electron volts and new thresholds near .25 electron volts and at .56 electron volts. New features were also observed in the .44 electron volt band, indicating that the defect for this level has a small lattice relaxation and Frank-Condon shift.

The structural and photoresponse properties of GaAs/{InAs quantum dot (QD)/InGaAs quantum well/GaAs} * m multiple quantum dot (MQD) structures with m from 1 to 20 placed in n-GaAs/i(MQD)/n-GaAs configuration to act as quantum dot infrared photodetectors (QDIPs) are described. The studies have highlighted the requirement for more quantitative modeling to guide optimal doping strategies and profiles to realize high photocurrents while maintaining acceptable dark current.

Wurtzite films were observed to exhibit strong absorption in the Restrahlen band as well as for the second harmonic of the Restrahlen band. The calculated transmittance T(E,d) was compared with the experimental curves as a mean of determining the damping factors associated with broadening of the Restrahlen bands due to phonon-phonon scattering and this results indicate that even when the thickness is reduced to the submicron level, the absorption for both harmonics is very significant.

The new advance in the area of II InAs/GaSb superlattices that have cutoff wavelength of ~3.7mum, is reported. The characteristic temperatures and the PL energy width were compared with those that have been reported for a similar cutoff wavelength in the material system.

We report here modified absorption property of colloidal quantum dots (CQDs) inside flexible Fano filters—made of patterned single crystalline silicon nanomembrane transferred onto flexible plastic substrates. Enhanced optical absorption was obtained both experimentally and theoretically, when the CQD absorption peak spectrally overlaps with Fano resonance peak. On the other hand, suppressed absorption was observed when the Fano resonance has no spectral overlap with the CQD absorption bands. [ABSTRACT FROM AUTHOR]

We demonstrate very-long-wavelength infrared type II InAs/GaSb superlattice photodiodes with a cutoff wavelength (λc,50%) of 17 μm. We observed a zero-bias, peak Johnson noise-limited detectivity of 7.63×109 cm Hz1/2/W at 77 K with a 90%–10% cutoff width of 17 meV, and quantum efficiency of 30%. Variable area diode zero-bias resistance-area product (R0A) measurements indicated that silicon dioxide passivation increased surface resistivity by nearly a factor of 5, over unpassivated photodiodes, and increased overall R0A uniformity. The bulk R0A at 77 K was found to be 0.08 Ω cm2, with RA increasing more than twofold at 25 mV reverse bias. [ABSTRACT FROM AUTHOR]