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We present the detailed characteristics of solid source molecular beam epitaxy (MBE) grown large format (640 × 512) extended short wavelength infrared In 0.83 Ga 0.17 As sensor with desirable performance at both pixel and focal plane array (FPA) levels. The FPA pixels in the mesa structure grown on a graded AlInAs buffer layer with 2.65-µm, 300-K cutoff wavelength exhibited 300-and 200-K peak detectivities as high as ∼2.5×10 10 and ∼1×10 12 cmHz 1/2 /W, which are both equivalent to the theoretical limits set by the Johnson noise of the detector. Dark current analysis of the pixels displayed no considerable tunneling component with the dark current being dominated by generation-recombination and shunt leakage mechanisms >200 K up to a reverse bias voltage of 3 V. Moreover, the noise measurements displayed no 1/ f noise in the FPA pixels. In spite of the large lattice mismatch, the FPA yielded very good response linearity, as well as impressively good responsivity nonuniformity and pixel operability of 5.5% and 99.8%, respectively. The results showing the feasibility of both solid source MBE and graded AlInAs buffer for the growth of extended InGaAs photodetectors are very encouraging for the large format FPA implementation of these detectors with desirable imaging performance and an extended cutoff wavelength as high as ∼2.7 µm.Index Terms-InGaAs, photodetector, short wavelength infrared.

We present the fabrication of large format 640 × 512, 15-µm pitch, mid-wave infrared region (MWIR) InAs/GaSb type-II superlattice (T2SL) focal plane array (FPA). In this report, the details of device design and fabrication processes are withheld adhering to the common practice of most of the manufactures and developers because of the strategic importance; however, information about fabrication processes of T2SLs FPA is presented to a certain extent. Comparison of etching techniques, passivation materials and methods, and substrate thinning (mechanical and chemical) is given besides of details regarding the standard ohmic contact and indium (In) bump formations. Morphological investigations of fabrication step are included. Large area pixels, 220 µm × 220 µm, fabricated by different etching methods and passivation materials/methods are compared in terms of dark current levels. Wet passivation with (NH 4) 2 S is discussed in terms of morphological investigations, and dark current results are compared with untreated samples. Large area pixel level characterizations as well as image level benchmarking of mechanical and chemical substrate thinning are reported. Effect of GaSb substrate on device performance and the way of reducing stress of In bumps are revealed. The importance of complete substrate removal is demonstrated through FPA images. Index Terms-Fabrication, focal plane array, infrared photodetectors, mid-wave infrared region, type-II superlattice. I. INTRODUCTION A N INFRARED device is fabricated by executing consecutive process steps that start with epilayer growth. Fabrication steps being well-established and feasible plays a decisive role in the performance of a device. Therefore, research groups and developers work constantly for reaching optimum fabrication processes in order to fabricate highly qualified sensors. For InAs/GaSb T2SLs, FPA fabrication is Manuscript

Using Landau mean field model, the spontaneous polarization and the dielectric susceptibility are analyzed as functions of temperature and pressure close to the cubic-tetragonal (ferroelectric-paraelectric) transition in BaTiO 3 . From the analysis of the dielectric susceptibility and the spontaneous polarization, the critical exponents are deduced in the classical and quantum limits for BaTiO 3 . From the critical behavior of the dielectric susceptibility, the spontaneous polarization can be described for the ferroelectric-paraelectric (cubic to tetragonal) transition between 4 and 8 GPa at constant temperatures of 0 to 200 K in BaTiO 3 within the Landau mean field model given here.

We report the high performance of Mid-wave Infrared Region (MWIR) InAs/GaSb Type-II Superlattice (T2SL) sensors with 640 × 512 format and 15-μm pixel pitch at both Focal Plane Array (FPA) and pixel level. The p-intrinsic-Barriern epilayer structure is adopted for this study, which is grown on 620 ± 30 μm thick GaSb substrate and highly-doped GaSb cap layer at the top structure. The mesa type pixels with sizes of 220 μm × 220 μm have dark currents 7.8 × 10 −12 A at 77 K both of which are equivalent to state-of-the-art values for Type-II Superlattice sensors. The various passivation techniques to lower the dark current are applied and the results are given in terms of dark current. Electro-optical measurements yielded comparable results to literature. After gathering data and optimizing the fabrication conditions, the FPA of 15-μm pitch having 4.92 μm cut-off wavelength (λ c ) shows 1.6 A/W peak responsivity, Noise Equivalent Temperature Difference (NETD) of 22.6 mK with optics of f/2.3, quantum efficiency larger than 65% and 99.75% operability. The acquired images by using aforementioned FPA device is presented in this paper. With the reduction of dark current, an encouraging imaging performance is obtained which shows the potential of the Type-II Superlattice detectors in 3 rd generation infrared sensors.