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The optical properties of the type-II lineup In x Al1−x N–Al0.59Ga0.41N/Al0.74Ga0.26N quantum well (QW) structures with different In contents are investigated by using the six-by-six K–P method. The type-II lineup structures exhibit the larger product of Fermi–Dirac distribution functions of electron f c n and hole ( 1 − f v U m ) and the approximately equal transverse electric (TE) polarization optical matrix elements ( | M x | 2 ) for the c1–v1 transition. As a result, the peak intensity in the TE polarization spontaneous emission spectrum is improved by 47.45%–53.84% as compared to that of the conventional AlGaN QW structure. In addition, the type-II QW structure with x ∼ 0.17 has the largest TE mode peak intensity in the investigated In-content range of 0.13–0.23. It can be attributed to the combined effect of | M x | 2 and f c n ( 1 − f v U m ) for the c1–v1, c1–v2, and c1–v3 transitions.

Temperature dependence of the optical properties of InGaN/GaN single quantum well light-emitting diodes (LEDs) with different indium (In) contents is investigated by using the effective mass theory taking into account the band-gap shrinkage and lattice thermal expansion. The peak intensity of the spontaneous emission spectrum is decreased by 30.6%, 30.4%, and 30.3% for the violet, blue, and green LEDs in the temperature range 300 K?400?K, while the reductions of internal quantum efficiency (?) with temperature are ~0.13, ~0.11, and ~0.1 respectively at the injection current density of 100 A cm?2. Moreover, two different slopes for all the ??T curves are observed: a lower absolute value of the slopes at T??=??300?350?K; a larger absolute value of the slopes at T??=??350?400?K. The numerical results also indicate that the efficiency droop effect with increasing the temperature becomes more serious, especially for the InGaN/GaN LED structures with the lower In-content.

The front-illuminated InP/InGaAs/InP PIN hetero-junction photovoltaic subpixels infrared detector has been achieved based on the lateral collection effect of photogenerated carriers. The photoresponse uniformity of the detector is carried out with a LBIC technique at different temperatures between 88 K and 296 K. With the aid of LBIC and the scanning capacitance microscopy (SCM) technique, the holes diffusion length Lp related to temperature was obtained. The result shows that the photoresponse uniformity decreases with temperature dropping, and Lp also varies directly in proportional to . The acoustic phonon scattering is the chief scattering mechanism existing in the detector with doped InGaAs (n ≈ 5×1016 cm−3) in the measured temperature range. The LBIC technique can be utilized effectively in the measurement of photoresponse uniformity of InGaAs infrared detectors, especially for the InGaAs subpixels detectors.