The dominant dark current mechanisms are identified and suppressed to improve the performance of midwave infrared InAs/GaSb type-II superlattice photodiodes at high temperatures. optimized heterojunction photodiode exhibits a quantum efficiency 50% for 2 μm thick active region without any bias dependence. At 150 K, R0A 5100 Ω cm2 specific detectivity 1.05×1012 cm Hz0.5/W demonstrated cutoff wavelength 4.2μm. Assuming 300 K background temperature 2π field view, detector is limited up 180...

We demonstrate the feasibility of InAs/GaSb/AlSb type-II superlattice photodiodes operating at short wavelength infrared regime below 3 μm. An n-i-p photodiode was grown with a designed cut-off 2 μm on GaSb substrate. At 150 K, exhibited dark current density 5.6 × 10−8 A/cm2 and front-side-illuminated quantum efficiency 40.3%, providing an associated shot noise detectivity 1.0 1013 Jones. The uncooled showed 2.2 10−3 41.5%, resulting in 1.7 1010

We present a hybrid photodetector design that inherits the advantages of traditional photoconductive and photovoltaic devices. The structure consists barrier layer blocking transport majority holes in p-type semiconductor, resulting an electrical due to minority carriers with low current density. By using M-structure superlattice as region, band alignments can be experimentally controlled, allowing for efficient extraction photosignal less than 50 mV bias. At 77 K, 14 μm cutoff detector...

Abstract Recent efforts to improve the performance of type II InAs/GaSb superlattice photodiodes and focal plane arrays (FPA) have been reviewed. The theoretical bandstructure models discussed first. A review recent developments in growth characterization techniques is given. MWIR (FPAs) reviewed latest results reported. It shown that these improvements has resulted background limited (BLIP) single element up 180 K. FPA shows a constant noise equivalent temperature difference (NEDT) 11 mK...

We report the influence of contact doping profile on performance superlattice-based minority carrier unipolar devices for mid-wave infrared detection. Unlike in a photodiode, space charge p-contact pMp device is formed with accumulated mobile carriers, resulting higher dark current highly doped p-contact. By reducing concentration layer, decreased by one order magnitude. At 150 K, 4.9 μm cut-off exhibit 2 × 10−5A/cm2 and quantum efficiency 44%. The specific detectivity 6.2 1011 cm Hz1/2/W at...

Recent improvements in the performance of type-II superlattice (T2SL) photodetectors has spurred interest developing low-cost and large-format focal plane arrays (FPAs) on this material system. Due to limitations size cost native GaSb substrates, GaAs is an attractive alternative with 8 wafers commercially available, but 7.8% lattice mismatched T2SL. In paper, we present a photovoltaic T2SL 320 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML"...

We report the growth and characterization of long wavelength infrared type-II InAs/GaSb superlattice photodiodes with a 50% cut-off at 11 μm, on GaAs substrate. Despite 7.3% lattice mismatch to substrate, passivated polyimide exhibit an R0A value 35 Ω cm2 77 K, which is in same order magnitude as reference devices grown native GaSb With reverse applied bias less than 500 mV, dark current density differential resistance-area product are close that within tolerance processing measurement. The...

We consider the problem of charge transport and recombination in semiconductor quantum well infrared photodetectors quantum-dot-in-a-well detectors. The photoexcited carrier relaxation is calculated using rigorous random-walk diffusion methods, which take into account finiteness cross sections, if necessary memory generation point. In present application, bias fields are high it sufficient to drift limited regime. photoconductive gain discussed a quantum-mechanical language, making more...

In recent years, the type-II superlattice (T2SL) material platform has seen incredible growth in understanding of its properties which lead to unprecedented development arena device design. Its versatility band-structure engineering is perhaps one greatest hallmarks T2SL that other platforms are lacking. this paper, we discuss advantages T2SL, specifically M-structure incorporates AlSb traditional InAs/GaSb superlattice. Using M-structure, present a new unipolar minority electron detector...

We report a type-II superlattice mid-wave infrared 320×256 imager at 81 K with the M-barrier design that achieved background limited performance (BLIP) and ∼99% operability. The 280 blackbody's photon irradiance was by an aperture band-pass filter from 3.6 μm to 3.8 resulting in total flux of ∼5×10(12) ph.cm(-2).s(-1). Under these low-light conditions, consequently use 13.5 ms integration time, observed be BLIP thanks ∼5 pA dark current 27 wide pixels. noise dominated read-out circuit which...

Type-II InAs/GaSb Superlattice (SL), a system of multi interacting quantum wells was first introduced by Nobel Laureate L. Esaki in the 1970s. Since then, this low dimensional has drawn lot attention for its attractive mechanics properties and grand potential emergence into application world, especially infrared detection. In recent years, superlattice photo-detectors have experienced significant improvements material quality, structural designs imaging applications which elevated...

Recent efforts have been paid to elevate the operating temperature of Type II superlattice Mid Infrared photon detectors. Using M-structure superlattice, novel device architectures developed, resulting in significant improvement performances. In this paper, we will compare different photodetector and discuss optimization scheme which leads almost one order magnitude electrical performance. At 150K, single element detectors exhibit a quantum efficiency above 50%, specific detectivity...

Infrared detection technologies entering the third generation demand performances for higher detectivity, operating temperature, resolution and multi-color detection, all accomplished with better yield lower manufacturing/operating costs. Type-II antimonide based superlattices (T2SL) are making firm steps toward new era of focal plane array imaging as witnessed in unique advantages significant progress achieved recent years. In this talk, we will present four research themes towards imagers...

Recent efforts have been paid to elevate the operating temperature of Type II InAs/GaSb superlattice Mid Infrared photon detectors. Optimized growth parameters and interface engineering technique enable high quality material with a quantum efficiency above 50%. Intensive study on device architecture doping profile has resulted in almost one order magnitude improvement electrical performance lifted up 300K-background BLIP operation 166K. At 77K, ~4.2 μm cut-off devices exhibit differential...

A method to handle the variation of band gap with temperature in direct band-gap III--V semiconductors and superlattices using an empirical tight-binding has been developed. The approach follows closely established procedures allows parameter variations which give rise perfect fits experimental data. We also apply far more complex problem structures type-II infrared for we have access original data recently acquired by our group. Given close packing bands small designs,...

The bandstructure tunability of Type II antimonide-based superlattices has been significantly enhanced since the introduction M-structure superlattice, resulting in significant improvements superlattice infrared detectors. By using M-structure, we developed pMp design, a novel photodetector architecture that inherits advantages traditional photoconductive and photovoltaic devices. This minority electron unipolar device consists an barrier layer blocking transport majority holes p-type...

Recent efforts to improve the performance of Type II InAs/GaSb superlattice photodiodes and focal plane arrays (FPA) have been reviewed. The theoretical bandstructure models discussed first. A review recent developments in growth characterization techniques is given. LWIR latest result reported. results both small large format FPAs, elevate operating temperature MWIR two color novel minority unipolar devices (pMp) finally photodiode FPA fabrication on GaAs substrates are

Abstract Comparing positron emission tomography (PET) systems which have different features is not straightforward. To address this, we propose to image the same object with all considered PET using a fixed scan time, and reconstruct from each an at predefined spatial resolution. With such resolution matched reconstructions, images should be identical except for their noise. Therefore, system that produces lowest variance has best performance. An analytical model described compute this...

We demonstrate optimization of continuous wave (cw) operation 4.6 μm quantum cascade lasers (QCLs). A 19.7 by 5 mm, double channel processed device exhibits 33% cw WPE at 80 K. Room temperature as high 12.5% is obtained from a 10.6 4.8 mm device, epilayer-down bonded on diamond submount. With the semi-insulating regrowth in buried ridge geometry, 15% with 2.8 W total output power mode room temperature. This accomplishment achieved systematically decreasing parasitic voltage drop, reducing...

There is a large variability in the features of existing (and future) positron emission tomography (PET) systems. This complicates comparison performance different systems for tasks. We propose mathematical model that estimates relative PET system imaging uniform cylinder particular diameter, attenuation and length, producing reconstructed image with spatial resolution. The assumed to be (approximately) cylindrical. computes an "effective sensitivity", taking into account solid angle covered...

InAs quantum dots embedded in InGaAs wells with InAlAs barriers on InP substrate grown by metalorganic chemical vapor deposition are utilized for high operating temperature detectors and focal plane arrays the middle wavelength infrared. This dot-well combination is unique because small band offset between well leads to weak dot confinement of carriers. As a result, device behavior differs significantly from that more common systems have stronger confinement. Here, we present energy level...

Recent efforts have been paid to elevate the operating temperature of Type II superlattice Mid Infrared photon detectors. Using M-structure superlattice, novel device architectures developed, resulting in significant improvement performances. In this paper, we will compare different photodetector and discuss optimization scheme which leads almost one order magnitude electrical performance. At 150K, single element detectors exhibit a quantum efficiency above 50%, specific detectivity...

In order to achieve quantitatively reliable images from Positron Emission Tomography (PET), scatter correction is necessary. By studying the energy measured for each event, useful information about spectrum of events obtained. This can be used correction. Efthimiou et al [1] proposed a method based on and moments estimate scatter. this study, we checked effects mashing data estimation model. Mashing combination multiple lines response into single one, reduce noise. al. Delayed Window perform...