High operating temperature InAs/GaSb type-II superlattice detectors on GaAs substrate for the long wavelength infrared (original) (raw)
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2019
The fabrication and characterization of InAs/GaSb type-II superlattice long-wavelength infrared (LWIR) photodetectors for high operating temperature (HOT) are assessed regarding possible device yield. We investigate laterally-operated photoconductors with a detector cutoff wavelength in the LWIR at an operating temperature accessible with 3-stage thermoelectric cooling, realized by suitably tailoring the layer composition. Type-II superlattices with a layer composition of 14 monolayers InAs and 7 monolayers GaSb are grown on semi-insulating 3-inch GaAs substrates. We report on the growth of three different buffer layer variants that serve as growth templates for GaSb-based layers on GaAs substrates. The characterization of 75 nominally equal single element detectors per sample evidences the reliability of device processing. The electro-optical evaluation of a randomly chosen subset indicates a high uniformity of responsivity and noise of LWIR InAs/GaSb HOT photoconductors. At 210 K,...
High-performance InAs/GaSb superlattice photodiodes for the very long wavelength infrared range
Applied Physics Letters, 2001
We report on the demonstration of high-performance p-in photodiodes based on type-II InAs/ GaSb superlattices with 50% cutoff wavelength c ϭ16 m operating at 80 K. Material is grown by molecular beam epitaxy on GaSb substrates with excellent crystal quality as evidenced by x-ray diffraction and atomic force microscopy. The processed devices show a current responsivity of 3.5 A/W at 80 K leading to a detectivity of ϳ1.51ϫ10 10 cmHz 1/2 /W. The quantum efficiency of these devices is about 35% which is comparable to HgCdTe detectors with a similar active layer thickness.
International Conference on Space Optics — ICSO 2018
We studied Ga-free InAs/InAsSb type-II superlattice (T2SL) in terms of period, thickness and antimony composition as a photon absorbing active layer (AL) of a suitable XBn structure for full mid-wavelength infrared domain (MWIR, 3-5µm) detection. The SL photodetector structures were fabricated by molecular beam epitaxy (MBE) on n-type GaSb substrate and exhibited cutoff wavelength between 5µm and 5.5µm at 150K. Electro-optical and electrical results of the device are reported and compared to the usual InSb MWIR photodiode.
Infrared Physics & Technology, 2014
Herein, we report a type II InAs/GaSb superlattice structure (SLS) grown on GaSb (100) substrates by molecular beam epitaxy (MBE) and its electrical characterization for mid-wavelength infrared detection. A GaSb buffer layer was grown under optimized SLS growth conditions, which can decrease the occurrence of defects for similar pyramidal structures. The complications associated with these conditions include oxide desorption of the substrate, growth temperature of the SLS, the V/III ratio during superlattice growth and the shutter sequence. High-resolution X-ray diffraction (HRXRD) shows the sixth satellite peak, and the period of the SLS was 52.9 Å. The atomic force microscopy (AFM) images indicated that the roughness was less than 2.8 nm. High-resolution transmission electron microscopy (HRTEM) images indicated that the SLS contains few structural defects related to interface dislocations or strain relaxation during the growth of the superlattice layer. The photoresponse spectra indicated that the cutoff wavelength was 4.8 µm at 300 K. The SLS photodiode surface was passivated by a zinc sulfide (ZnS) coating after anodic sulfide.
Mid-wavelength infrared type-II InAs/GaSb superlattice interband cascade photodetectors
Optical Engineering, 2014
Recently, a new strategy to achieve high-operating temperature (HOT) infrared photodetectors to include cascade devices and alternate materials such as type-II superlattices has been observed. Another method to reduce dark current is related to the limitation of the volume of detector material via a concept of a photon-trapping detector. The performance of an innovative HOT detector designing so-called interband (IB) cascade type-II MWIR InAs/GaSb superlattice detectors is presented. Detailed analysis of the detector's performance (such as dark current, RA product, current responsivity, and response time) versus bias voltage and operating temperatures (220 to 400 K) is performed, pointing out the optimal working conditions. At the present stage of technology, the experimentally measured R 0 A values of the IB cascade type-II superlattice detectors at room temperature are higher than those predicted for HgCdTe photodiodes. It is shown that these HOT detectors have emerged as the competitors of HgCdTe photodetectors.
Applied Physics Letters, 2010
We report here a heterojunction band gap engineered type-II InAs/GaSb strained layer superlattice photodiode for longwave infrared detection. The reported PbIbN architecture shows improved performance over conventional PIN design due to unipolar current blocking layers. At 77 K and V b = −0.25 V, responsivity of 1.8 A/W, dark current density of 1.2 mA/ cm 2 , single pass quantum efficiency of 23%, and shot noise limited detectivity ͑D ء ͒ of 8.7ϫ 10 10 cm Hz 1/2 W −1 ͑ c = 10.8 m͒ were measured. The device demonstrated background limited performance at 100 K under 300 K for 2 field of view.
New Ga-Free InAs/InAsSb Superlattice Infrared Photodetector
Proceedings of the 6th International Conference on Photonics, Optics and Laser Technology
We studied Ga-free InAs/InAsSb type-II superlattice (T2SL) in terms of period, thickness and antimony composition as a photon absorbing active layer (AL) of a suitable XBn structure for full mid-wavelength infrared domain (MWIR, 3-5µm) detection. The SL photodetector structures were fabricated by molecular beam epitaxy (MBE) on n-type GaSb substrate and exhibited cutoff wavelength between 5µm and 5.5µm at 150K. Electro-optical and electrical results of the device are reported and compared to the usual InSb MWIR photodiode.