In this paper, the flexibility of long-wavelength Type-II InAs/GaSb superlattice (Ga-containing SL) is explored and investigated from the growth to the device performance. First, several samples with different SL period composition and thickness are grown by molecular beam epitaxy. Nearly straincompensated SLs on GaSb exhibiting an energy band gap between 105 to 169 meV at 77K are obtained.Second, from electronic band structure calculation, material parameters are extracted and compared for the different grown SLs. Finally, two p-i-n device structures with different SL periods are grown and their electrical performance compared. Our investigation shows that an alternative SL design could potentially be used to improve the device performance of diffusion-limited devices for long-wavelength infrared detection.

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We report on a high-performance mid-wavelength infrared avalanche photodetector (APD) with separate absorption and multiplication regions. InAs is used as the absorber material and high-bandgap AlAs 0.13 Sb 0.87 is used as the multiplication material. At room temperature, the APD’s peak response wavelength is 3.27 μm, and the 50% cutoff wavelength is 3.5 μm. The avalanche gain reaches 13.1 and the responsivity is 8.09 A/W at 3.27 μm when the applied reverse bias voltage is 14.6 V. The measured peak detectivity D ⋆ of the device is 2.05 × 10 9    cm · Hz 0.5 / W at 3.27 μm.

We report on a 10 lm InAs/GaSb type-II superlattice (T2SL) grown by molecular beam epitaxy on a GaAs substrate using an interfacial misfit (IMF) array and investigate the optical and structural properties in comparison with a T2SL grown on a GaSb substrate. The reference T2SL on GaSb is of high structural quality as evidenced in the high-resolution x-ray diffraction (HRXRD) measurement. The full width at half maximum (FWHM) of the HRXRD peak of the T2SL on GaAs is 5 times larger than that on GaSb. The long-wave infrared (LWIR) emission spectra were analyzed, and the observed transitions were in good agreement with the calculated emission energies. The photoluminescence (PL) intensity maxima (I max )o f$10 lm at 77 K is significantly reduced by a factor of 8.5 on the GaAs substrate. The peak fitting analysis of the PL profile indicates the formation of sub-monolayer features at the interfaces. PL mapping highlights the non-uniformity of the T2SL on GaAs which corroborates with Nomarski imaging, suggesting an increase in defect density.

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