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A two terminal extended short wavelength infrared heterojunction phototransistor based on type-II InAs/AlSb/GaSb on a GaSb substrate is designed, fabricated, and investigated. With the base thickness of 40 nm, the device exhibited a 100% cut-off wavelength of ∼2.3 μm at 300 K. The saturated peak responsivity value is 320.5 A/W at 300 K, under front-side illumination without any antireflection coating. A saturated optical gain of 245 at 300 K was measured. At the same temperature, the device exhibited a collector dark current density (at unity optical gain) and a DC current gain of 7.8 × 10−3 A/cm2 and 1100, respectively. The device exhibited a saturated dark current shot noise limited specific detectivity of 4.9 × 1011 cm·Hz1/2/W at 300 K which remains constant over a broad range of wavelengths and applied biases. [ABSTRACT FROM AUTHOR]

We report the growth and characterization of mid-wavelength infrared type-II InAs/InAs1−xSbx superlattice photodiodes on GaSb substrates grown by metal-organic chemical vapor deposition. At 150 K, the 50% cut-off wavelength is 5.0 μm, the dark current density is 3.3 × 10−4 A/cm2 under −20 mV bias, and the peak responsivity is 1.76 A/W corresponding to a quantum efficiency of 55% without anti-reflection coating. A specific detectivity of 1.2 × 1011 cm Hz1/2/W is achieved at 4.0 μm under −20 mV bias at 150 K. [ABSTRACT FROM AUTHOR]

InAs/GaSb/AlSb type-II superlattice-based photodetectors, with 50% cut-off wavelength of 2.1 $\mu \text{m}$ and a −3 dB cut-off frequency of 4.8 GHz, are demonstrated, for 10 $\mu \text{m}$ diameter circular mesas under 15 V applied reverse bias. A study of the cut-off frequency with applied bias and mesa size was performed to evaluate some of the limiting factors of photodetectors high frequency performance. [ABSTRACT FROM AUTHOR]

The use of nanoengineered metallic complex mediums in the monitoring of urine is investigated in this study. As to the mediums used, nanoscaled thin films comprised of (i) copper nanohelix structures of two different numbers of helical turns and (ii) columnar thin films of copper nanorods of two different slanting angles grown over planar glass surface – a dielectric medium – are taken into account. Turbadar–Kretschmann–Raether (TKR) configuration is used to couple light with the metallic nanoengineered thin films, and the absorption spectra are monitored corresponding to two different optical wavelengths. The void regions in nanoengineered metallic films are filled up with urine as the analyte, which causes to alter the constitutive properties, resulting thereby shifts in the peaks in absorption spectra. Prominent shifts in absorption peaks corresponding to nanoengineered mediums infiltrated with urine essentially confirm prudent optical sensing characteristics of the devices under consideration. [ABSTRACT FROM PUBLISHER]

We demonstrate low noise short wavelength infrared (SWIR) Sb-based type II superlattice (T2SL) avalanche photodiodes (APDs). The SWIR GaSb/(AlAsSb/GaSb) APD structure was designed based on impact ionization engineering and grown by molecular beam epitaxy on a GaSb substrate. At room temperature, the device exhibits a 50% cut-off wavelength of 1.74 µm. The device was revealed to have an electron-dominated avalanching mechanism with a gain value of 48 at room temperature. The electron and hole impact ionization coefficients were calculated and compared to give a better prospect of the performance of the device. Low excess noise, as characterized by a carrier ionization ratio of ~0.07, has been achieved. [ABSTRACT FROM AUTHOR]

• High-speed T2SLs based heterojunction phototransistors have been demonstrated. • The influence of different parameters on device performance has been investigated. • The trade-off between the high-speed performance and optical gain has been showed. In this study, high speed performance of heterojunction phototransistors (HPTs) based on InAs/GaSb/AlSb type-II superlattice with 30 nm base thickness and 50% cut-off wavelength of 2.0 μm at room temperature are demonstrated. We studied the relationship between −3 dB cut-off frequency of these HPT versus mesa size, applied bias, and collector layer thickness. For 8 μm diameter circular mesas HPT devices with a 0.5 μm collector layer, under 20 V applied bias voltage, we achieved a −3 dB cut-off frequency of 2.8 GHz. [ABSTRACT FROM AUTHOR]