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Background Personal watercrafts (PWC) account for a disproportionate amount of water based injuries. Current literature suggests those with less PWC experience are more at risk for injury. Previous studies have not specifically evaluated the orthopedic implications of PWC usage or how various mechanisms of injury (MOI) contribute to different injury patterns. Hypothesis PWC injuries will frequently require orthopedic intervention. The presence of an orthopedic injury will result in increased injury severity score (ISS), hospital and intensive care unit (ICU) length of stay (LOS). Patients visiting our region will have less PWC experience and so are more prone to serious injuries. Materials and methods Retrospective cohort study at a single Level 1 trauma center of admitted patients sustaining PWC injuries from 02/2004–03/2017. The following were studied: demographics, mechanism, season, ISS, hospital and ICU LOS, follow-up, fracture characteristics and management. Results Hundred and twenty-seven patients were admitted due to PWC injury, 66 (52.0%) sustained an orthopedic injury, totaling 103 fractures (48 [46.6%] lower extremity, 26 [25.2%] upper extremity, 14 [13.6%] vertebral, 11 [10.7%] pelvic ring and 4 [3.9%] acetabulum). The mean age of orthopedic patients was 29 years (range 8–62). Handle bar injuries were significantly associated with open fractures, (13 of 25 open fractures, 3 of which became infected). Injuries occurring during the winter were associated with a higher ISS, yet more injuries occurred in the summer. A patient being a “visitor” to the region did not influence ISS. The mean LOS was 12.6 days for orthopedic patients. Eighteen orthopedic patients (27.3%) required ICU admission and 36 (54.5%) patients required orthopedic surgery (mean 2.11 operations). Discussion A majority of PWC injuries resulted in extremity fractures with a moderate percentage requiring orthopedic surgery. Correlations between PWC experience and injury incidence can provide information for increased safety. Level of evidence IV; retrospective.

Graphene films are one of the most favorable candidates for next generation transparent conductive electrodes (TCEs) for electrical devices, because of its unique electronic structure. Furthermore, an optical transparency of graphene films surpasses a transparency of conventional TCE such as indium tin oxide (ITO). However, actual graphene anode for OLEDs and OPVs has several problems owing to its low work function and high sheet resistance. Here, we have demonstrated enhanced performance of OLEDs by using hybrid anodes composed of graphene and conducting polymer (poly(3,4-ethylenedioxythiophene) with poly(styrenesulfonic) (PEDOT:PSS)), which can overcome low work function and high sheet resistance. PEDOT:PSS plays a role in improving the conductivity and forming a work function stairs for smooth hole injection property. As a result, we achieved enhanced OLED efficiencies using graphene-conducting polymer hybrid anode. These results are superior to that in efficiencies of graphene anode devices. Our experimental results indicate that graphene and conducting polymer would be next generation and alternative TCEs for OLED and OPV.

Highly selective and low damage etching of the GaAs cap layer on AlGaAs is essential in fabricating GaAs/AlGaAs high electron mobility transistors. The GaAs on AlGaAs was etched using a low energy Cl2/O2 neutral beam and the Schottky device characteristics fabricated on the exposed AlGaAs were compared with those fabricated after the etching using wet etching and a Cl2/O2 ion beam. Using a low energy Cl2/O2 ion beam or a Cl2/O2 neutral beam, highly selective etching of the GaAs cap layer to AlGaAs similar to wet etching could be achieved through the formation of Al2O3 on the exposed AlGaAs during the etching. When the electrical characteristics of the Schottky devices were compared, the devices fabricated after the etching using the neutral beam showed the best electrical characteristics such as electrical stability, low leakage current, higher barrier height, etc. by showing low damage to the exposed AlGaAs surface.

Background Personal watercrafts (PWC) account for a disproportionate amount of water based injuries. Current literature suggests those with less PWC experience are more at risk for injury. Previous studies have not specifically evaluated the orthopedic implications of PWC usage or how various mechanisms of injury (MOI) contribute to different injury patterns. Hypothesis PWC injuries will frequently require orthopedic intervention. The presence of an orthopedic injury will result in increased injury severity score (ISS), hospital and intensive care unit (ICU) length-of-stay (LOS). Patients visiting our region will have less PWC experience and so are more prone to serious injuries. Materials and methods Retrospective cohort study at a single level 1 trauma center of admitted patients sustaining PWC injuries from 02/2004–03/2017. The following were studied: demographics, mechanism, season, ISS, hospital and ICU LOS, follow-up, fracture characteristics and management. Results Overall, 127 patients were admitted due to PWC injury, 66 (52.0%) sustained an orthopedic injury, totaling 103 fractures [48 (46.6%) lower extremity, 26 (25.2%) upper extremity, 14 (13.6%) vertebral, 11 (10.7%) pelvic ring and 4 (3.9%) acetabulum]. The mean age of orthopedic patients was 29 years (range: 8–62). Handle bar injuries were significantly associated with open fractures, (13 of 25 open fractures, 3 of which became infected). Injuries occurring during the winter were associated with a higher ISS, yet more injuries occurred in the summer. A patient being a “visitor” to the region did not influence ISS. The mean LOS was 12.6 days for orthopedic patients. Eighteen orthopedic patients (27.3%) required ICU admission, and 36 (54.5%) patients required orthopedic surgery (mean: 2.11 operations). Discussion A majority of PWC injuries resulted in extremity fractures with a moderate percentage requiring orthopedic surgery. Correlations between PWC experience and injury incidence can provide information for increased safety. Level of evidence IV; retrospective.

An electrophoretic display using Ti0 2 particles is the most promising candidate because it offers various advantages such as ink-on-paper appearance, good contrast ratio, wide viewing angle, image stability in the off-state and extremely low power consumption. The core technology of electrophoretic display is dispersion controlling of TiO 2 nano particles in nonaqueous solution. To prepare an ink for electronic paper using TiO 2 nano particles, cyclohexane with low dielectric constant and transparency, polyethylene for producing polymer coating layer which reduces apparent density of Ti0 2 , and TiO 2 nano powders were intermixed using planetary-mill. The zeta-potential value of Ti0 2 particles in cyclohexane was measured about -40 mV, but was measured over -110 mV by dispersant attached to polyethylene-coated TiO 2 surface. Prepared electronic ink was filled in cross patterned micro-wall with 200 μm in width and 40 μm in height on ITO glass designed by photolithography. The response time of electronic paper evaluated by mobility of TiO 2 particle between micro-walls was measured 0.067sec, but the drift velocity from reflectance wave form during reverse turn of electronic ink was measured 0.07cm/sec.

In this study, we fabricated the ultra-thin fiber-optic dosimeter (UTFOD) for high energy photon beam therapy dosimetry. The UTFOD has high spatial resolution due to the relatively small volume compared to conventional dosimeters therefore the UTFOD can measure depth doses precisely in build-up regions of therapeutic radiation beams. For 10 MV photon beams, we measured the scintillation signal generated from the UTFOD according to monitor units (MUs) and dose rates of the clinical linear accelerator (CLINAC). Also, we measured percentage depth doses (PDDs) at different depths of solid water phantoms using the UTFOD and the GAFCHROMIC ® EBT films, and the results were compared with those using the Monte Carlo N-Particle eXtended (MCNPX) code.

In this paper, we report novel (TE-free) FRAM capacitors using reliable PZT CMP process in order to improve ferroelectric properties and enhance mass productivity by simplifying integration of processes. FRAM capacitors were prepared using a PZT film for a stopping layer in ILD CMP using a high selective slurry having a very low PZT removal rate relative to oxide removal rate. Noble metal electrode (TE) and contact (TEC) of conventional (TE/FE/BE) capacitors are not desirable for integration of high-density FRAM device and mass production due to contact etch damage and poor etch and deposition properties of Ir. We investigated the structural and electrical characteristics of MOCVD PZT films grown on Ir bottom electrode before and after PZT CMP process. Even though some degradation in polarization hysteresis of polished PZT capacitors was observed compared to as-deposited capacitors due to interface effect between PZT film and top electrode, electrical properties such as leakage current and fatigu...

Formation behavior and photo-oxidation abilities of nanostructured TiO2 powders were investigated through a direct crystallization from aqueous TiOCl2 solutions containing various metal chlorides at 100??C. The obtained TiO2 powders without any additives and those with Ni2+, Fe3+ and Nb5+ ions added, which have a similar positive ionic radius to Ti4+, were mainly crystallized with rutile phase, whereas those with Al3+ and Zr4+ ions added, which have a quite different positive ionic radius, were mainly crystallized with anatase phase. On the other hand, the secondary particles in the TiO2 powder consisted of acicular and spherical primary particles, corresponding to rutile and anatase phases, respectively. From these results, it seems that the positive ionic radius of the additives would affect phase formation as well as morphology of TiO2 precipitates. Among the TiO2 powders prepared, Ni-added powder, which consisted mainly of rutile phase with a small amount of anatase phase, showed excellent photocatalytic ability in decomposition of 4-chlorophenol.

Research concern about neutron radiography has been increasing in Korea since 2001. Neutron radiography can help for the weakness of X-ray image. Neutron radiography can be used in not only non-destructive inspection but also basic science research. For those reasons more compact mono-energetic neutron source is needed. The 4 MeV deuteron cyclotron can be a candidate for the production of mono-energetic neutrons. In this paper optimal 4 MeV deuteron cyclotron magnet design is shown for neutron generation by d(d, n)He reaction. All field simulations have been performed using POSSION and OPERA-3D (TOSCA) for magnet system design. The required beam current is 1 mA, 4 MeV. The first purpose of this cyclotron is to generate fast neutrons with deuterium gas target. The second purpose of this cyclotron is material science and nuclear technology research in biology, physics and chemistry. Also it will be used in industries including neutron radiography.

In this work, we use the electrical method to coat graphene oxide (GO) on ITO (Indium Tin Oxide) glass. The coated GO was characterized by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The coated surface was monitored by scanning electron microscope (SEM) and atomic force microscope (AFM). Based on this coating method, we can control the thickness of GO film by changing the applied voltage. Result of thickness control was analyzed by AFM and transmittance measurement. Also this method can selectively deposition of GO film is possible on patterned ITO. This result was confirmed by Raman spectroscopic mapping.

Measurements of 77K RoA and 300K reverse bias dynamic impedance (RdA) products at one volt reverse bias has been carried out to assess the degree of correlation of this figure of merit. Planar P-on-n heterostructures were grown on near lattice-matched CdZnTe substrates with Hg1-xCdxTe (0.20< x

Temperature and time dependent Hg-annealing studies for arsenic activation have been carried out on As-doped molecular beam epitaxy HgCdTe eitherin situ or by ion implantation to determine the extent of arsenic activation in the single layer. Enhanced As diffusion and activation in double layer heterostructures have also been investigated to further our understanding of the effects on zero bias resistance-area product (RoA) and quantum efficiency. The results show that the arsenic activation anneal is limited by Hg self-diffusion into the HgCdTe epilayer. Using this arsenic activation process for eitherin situ doped arsenic or implanted arsenic, high performance p-on-n double layer heterostructure photodiodes have been demonstrated on both mesa and planar device structures.

We have carried out a study and identified that MBE HgCdTe growth-induced void defects are detrimental to long wavelength infrared photodiode performance. These defects were induced during nucleation by having surface growth conditions deficient in Hg. Precise control and reproducibility of the CdZnTe surface temperature and beam fluxes are required to minimize such defects. Device quality material with void defect concentration values in the low 102 cm2 range were demonstrated.

E.O. Fischer's red crystalline modification of tris-cyclopentadienylbismuth, Bi(C 5 H 5 ) 3 , was obtained by acid-base reaction of tris(dialkylamino)bismuth compounds with monomeric cyclopentadiene in THF. Crystallisation from ether gave transparent deep red crystals in 70% yield; as a by-product of this reaction, a polymeric, monovalent bismuth compound, cyclopentadienylbismuth (I), (BiC 5 H 5 ) ∞ , was also isolated. The crystal structure of “red Bi(C 5 H 5 ) 3 ” has been determined at −70°C by single crystal X-ray diffraction methods: monoclinic crystals, space group P2/ 1 /c , a = 898(4) b = 8.684(3), c = 17.945(7)A, β = 110.10(4)° and Z = 4. On exposure to light a colour change is observed from transparent red to opaque red which is maintained at 15°C. Warming to 20°C the material rapidly turns black. This colour change phenomenon is probably a result of the interaction of the bismuth atom of one molecule with one cyclopentadienyl ligand of a neighbouring molecule of Bi(C 5 H 5 ) 3 .

Purified recombinant poliovirus polypeptide 3AB interacts with 3CDpro and 3Dpol as shown by coimmunoprecipitation with anti-3Dpol antibodies. A consequence of this interaction is an accelerated autoprocessing of 3CDpro to produce 3Cpro and 3Dpol. The activation of 3Dpol polymerase activity by cleavage of 3CDpro, a polypeptide that has no polymerase activity, can be shown by template- and primer-dependent poly(U) synthesis. Anti-VPg antibodies (VPg = 3B) added to HeLa translation extracts programmed with poliovirion RNA inhibit cleavage of 3CDpro whereas addition of purified 3AB or VPg to these translation reactions increases 3CDpro processing. 3AB stimulates also 3Cpro-related proteolysis of 2BC, a poliovirus-specific, nonstructural processing intermediate. In contrast, 3CDpro-specific cleavage of the structural precursor P1 is inhibited by the addition of 3AB as shown by a decrease in the production of VP0 and VP3. These data shed new light on a phenomenon in the regulation of expression of poliovirus genetic information: whereas the proteinase 3CDpro is needed for processing of the capsid precursor, the cleavage product of this relatively stable precursor is required for RNA replication.

We recently succeeded in fabricating planar Hg1−yCdyTe/Hg1−xCdxTe (x

We devised and demonstrated terahertz emission from an optical fiber tip coated with InAs thin film illuminated by guided laser field and achieved λ/20 sub-wavelength imaging in an InAs-based transmissive near-field laser emission THz microscope.

Several dynamic analysis techniques are compared with a planar vehicle model. Cartesian formulation, suspension superelement technique, velocity transformation, and recursive formula are compared. The relation between the recursive formula and velocity transformation is investigated. When those techniques are applied to a planar vehicle with two independent suspensions, the efficiency of those methods was compared. The computational efficiency of the recursive formula was higher than those of other methods for the specific planar vehicle example.

Human papillomavirus (HPV) is a major causative agent of anogenital warts and a necessary cause of cervical cancer. This report will serve to assess the safety and immunogenicity of quadrivalent (types 6, 11, 16, and 18) HPV L1 virus-like particle (VLP) vaccine in the Korean population. We performed a randomized, double-blind, placebo-controlled study in 176 volunteers aged 9–23 years. Using a 2:1 ratio for randomization, 117 women were assigned to quadrivalent HPV (20 μg type 6, 40 μg type 11, 40 μg type 16, and 20 μg type 18) vaccine and 59 women to placebo. Individuals received vaccine at day 1, month 2, and month 6 and provided blood samples for analysis at enrollment at month 7. Analyses were done as specified in the study protocol. Quadrivalent HPV vaccine was generally well tolerated, with no vaccine-related serious adverse experiences. Quadrivalent HPV vaccine induced seroconversion for each vaccine-related HPV type. At month 7, vaccine-induced type-specific antibody titer was high. In conclusion, administration of quadrivalent HPV VLP vaccine to Korean women aged 9–23 years was generally well tolerated and highly immunogenic

In this paper, we examine numerically and experimentally the linear beam optics distortion in the storage ring of the Pohang Light Source (PLS), and the correction of optics using a number of quadrupole magnets installed in the storage ring. The measured orbit‐response matrices were fitted to the model‐response matrices to obtain β and dispersion functions in storage ring. By readjusting currents of quadrupole‐magnet power supplies, optics parameters were successfully restored to the values very close to the design ones. After the optics correction, it is expected that the performance of the storage ring is better than the present one.

We report a process to fabricate planar Hg1−yCdyTe/Hg1−xCdxTe (x

While a variety of light‐detecting devices have been made with HgCdTe, little has been done to apply this technology to light‐emitting devices. We report here the successful fabrication and operation of the first HgCdTe injection laser. This stripe‐geometry double‐heterostructure laser was operated under pulsed current at temperatures between 40 and 90 K. At 77 K, the emission wavelength was 2.86 μm with a linewidth of 0.3 meV, and the pulsed threshold current density was 625 A/cm2. The double heterostructure, with a 1.4‐μm‐thick active layer, was grown and in situ doped by molecular beam epitaxy (MBE). The p+ and n+ confinement layers were doped with arsenic and indium, respectively.

Polishing pressure in the damascene process for BLT thin films improves the removal rate and surface roughness; however, the electrical properties of BLT capacitors fabricated by the damascene process with high pressure worsened. Therefore, low pressure was suitable for BLT capacitors fabricated by the damascene process when considering the electrical properties.

This work examines the electron field emission characteristics of polycrystalline diamond films at high temperatures. Diamond is an excellent material as a field emitter because its high mechanical hardness and chemical inertness enable robust reliability. Diamond is also a wide-band gap semiconductor, increasing the probability for selective emission of higher-energy electrons. In recent years, considerable interest has developed in energy conversion applications of polycrystalline diamond films. However, little work has been considered for the field emission characteristics of diamond at elevated temperatures. The motivation behind this study involves direct energy conversion applications in power generation systems, where high temperatures exist. N-doped polycrystalline diamond films were grown by plasma-enhanced chemical-vapor deposition (PECVD). To investigate the effect of increased temperatures on field emission, current-voltage measurements were taken from the same diamond film at varying temperatures. Results from these measurements indicate a decrease in the turn-on voltage with increasing temperature. Further analysis of the temperature dependency of diamond was achieved through the parameter estimation of the effective emitting area, field enhancement factor, and work function. These results suggest that high-energy electrons are responsible for improved emission at high temperature. The resulting possibilities for direct energy conversion via diamond field emission are considered and discussed.

This study deals with the effects of perturbing the surfaces of unpassivated HgMnCdTe and HgCdTe short‐wavelength infrared photodiodes to further our understanding of these effects on dark currents. Perturbations include illuminating ultraviolet (UV)radiation in high vacuum and in various gaseous species. The change in dark current at 0.8 V reverse bias and its evolution with time was monitored in situ. By correlating the amount of excess dark current generated by UV radiation to the vacuum conditions, we conclude that it is a surface‐related problem. A drastic improvement in device performance was found by illuminating its surface with UV radiation in high vacuum. This simple treatment prevents the generation of excess and persistent dark current and stabilizes the leakage current at low reverse bias. This can be understood in terms of photodesorption of surfacecontaminants which induce deep level surface states, giving rise to the persistent dark current generation. By studying the effects of various gaseous species, we identified water molecules as the key surfacecontaminants. We also discovered an anomalous degradation in HgCdTe diodes when they were exposed to hydrogen and UV radiation simultaneously. This anomalous degradation can be interpreted as UV‐catalyzed chemical reduction of HgCdTe by hydrogen or the diffusion of hydrogen atoms into the bulk to change the junction characteristics.

A new device concept for CdTe gamma ray detectors has been demonstrated using p+(HgCdTe)-n(CdTe)-n+ (HgCdTe) diode structures. Both P+ and n+ Hg0.25Cd0.75Te epilayers were grown by the liquid phase epitaxy (LPE) technique on semi-insulating CdTe sensor elements. The LPE grown P-I-N structure offers potential advantages for p-n junction and ohmic contact formation over standard ion implanted diodes or Schottky barrier devices. Detectors with active areas of 2 mm2 were fabricated. Resolutions of 10 KeV were obtained for the 122 KeV gamma peak of Co57 at room temperature.

Thin epitaxial HgCdTe/CdTe photodiodes are shown to have lower dark current noise than similar thick devices. This is explained by the limited-diffusion-volume model which requires a thin diode and a low surface recombination rate. Electron beam induced current is used for characterizing minority electrons distribution; the characteristic interface recombinations(L/D) has been found to be equal to 0.05 at 80 and 210 K.R 0 A measurements give values consistent with this model.

The isothermal vapor‐phase‐epitaxial (ISOVPE) growth of device‐quality HgCdTe layers on both CdTe and CdTe/Al2O3 substrates has been demonstrated. The material and device properties on both types of substrates have been studied and compared with reported values for HgCdTe grown by other techniques. The as‐grown ISOVPE Hg1−xCdxTe (x≂0.3) epilayers are always p type with carrier concentrations of ∼5×1015 to 3×1016 cm−3 and mobilities of ∼230–260 cm2/V s at 77 K. The temperature and compositional dependence of electrical properties of ISOVPE Hg1−xCdxTe are somewhat different from those of liquid‐phase epitaxy (LPE) and bulk HgCdTe. In particular, the acceptor ionization energy, EA =7 meV, is about half that obtained in midwavelength infrared LPE or bulk HgCdTe, and nearly independent of composition x. The R0A product of a representative photodiode (λc ≂4.65 μm, 77 K) is 2×106 and 4 Ω cm2 at 77 and 195 K, respectively, with comparable device qualities seen on both CdTe and CdTe/Al2O3 substrates.

Long and middle wavelength infrared (LWIR, MWIR) p+‐n photodiodes have been fabricated with Hg1−xCdxTe (0.20

Hg1−xCdxTe epilayers with a wavelength of ∼1.33 μm have been successfully grown by liquid phase epitaxy. Photodiodes were fabricated and measured. Analysis of the heterojunctions indicates that at room temperature the junction current at forward bias is dominated by a generation‐recombination mechanism. The generation‐recombination effective lifetime was estimated to be 2×10−7 s. A leakage current density of 9×10−6 A/cm−2 was observed at a reverse bias of 30 V, and the diode breakdown voltage was 70 V.

Device‐quality Hg1−xCdxTe (0.26

A planar HgCdTe/CdTe avalanche photodiode with peak responsivity at 1.22 μm and cutoff at 1.25 μm has been fabricated successfully by liquid phase epitaxy (LPE). Avalanche gains of higher than 15 have been obtained with 1.06‐μm Nd:yttrium aluminum garnet (YAG) laser illumination. A reverse breakdown voltage of 80 V and a leakage current density of 1×10−4 A/cm2 at 40 V were measured. The peak quantum efficiency at 1.22 μm is 72% without any antireflection coating.

Infrared photodiodes fabricated with HgCdTe epilayers grown on GaAs substrates by molecular beam epitaxy (MBE) are reported here for the first time. Growth was carried out on the (211)B orientation of GaAs, and the as‐grown epilayer (x=0.24) was p type. The n‐p junction was formed by Be ion implantation, the resistance‐area product (R0 A) at zero bias was 1.4×103 Ω cm2 , the wavelength cutoff was 8.0 μm, and the quantum efficiency was 22%; all were measured at 77 K. We show that in the diffusion regime diodes fabricated with MBE HgCdTe/GaAs have comparable R0 A product values to those made with HgCdTe grown by bulk techniques. This result discloses new possibilities for advanced monolithic HgCdTe devices based on GaAs integrated circuit technology.

Device‐quality Hg1−xCdxTe (0.2≤x≤0.35) epitaxial layers have been grown on CdTe substrates by open‐tube isothermal vapor phase epitaxy (ISOVPE). The surface morphology of the layers is mirrorlike, and the Hall data are comparable to those for HgCdTe grown by liquid phase epitaxy (LPE). Photovoltaic devices with a cutoff wavelength of 4.1 μm at 77 K were fabricated on an ISOVPE HgCdTe epilayer. Their performance is comparable with those that we have obtained for such devices fabricated on LPE HgCdTe epilayers.

High‐performance HgCdTe photodiodes have been formed by successive growth of p‐ and n‐type epitaxial layers on CdTe substrates via the liquid phase epitaxy technique. These diodes exhibit high resistance‐area (R0 A) products at high temperatures: R0 A products of 1 and 30 Ω cm2 have been observed at 283 and 200 K, respectively, for Hg0.68Cd0.32Te (λco=4.0 μm at 200 K). The saturation current density for the grown junction photodiode at 300 K is 0.12 A/cm2.

This paper reports the material and device characteristics of epitaxial HgCdTe/CdTe heterostructures with cut-off wavelength from 8 to 14 µm at 77K. The HgCdTe layer was grown by a vertical dipping liquid phase epitaxy (LPE) technique. The as-grown layers were p-type with hole concentration on the order of 1017cm-3. The layers exhibited exceptionally good composition uniformity; Cd composition varied o A products of the epitaxial diodes are currently comparable to those of the bulk diodes.

Hgi-xCdxTe epitaxial layers have been successfully grown in various compositions, for 1-3 μm applications. n+/p junctions are formed either by a standard B-implantation into as-grown p-type layers or by doubly grown p- and n-layers. The SWIR HgCdTe photodiodes exhibit quantum efficiencies of 55-65% without AR coating. For the diodes with 1.39 μm cut-off at room temperature, the zero bias detector resistance-area (RoA) product is 4 x 10 4 Ω-cm2, and the dark current density is ~ 1 x 10 -4 A/cm2 at half-breakdown voltage. The same values of ~ 104 Ω-cm2 RoA products have also been measured for 2.4 μm cut-off photodiodes at 195K. The energy gap and temperature dependence of RoA product is in excellent agreement with the bulk limited generation-recombination model. The breakdown voltages of SWIR diodes vary from 12 volts to greater than 130 volts, depending on the Cd composition (x) and base carrier concentrations.

HgMnCdTe/CdTe photodiodes with responsivity cutoffs of up to 1.54 pm have been fabricated by liquid phase epitaxy (LPE). The mesa device structure consists of a boron-implanted mosaic fabricated on a p-type Hg1−x−yMnxCdyTe layer grown on a CdTe substrate. A reverse breakdown voltage (VB) of 50 V and a leakage current density of 1.5 × 10−4 A/cm2 at V = −10 V was measured at room temperature (295K). A 0.75 pF capacitance was also measured under a 5 V reverse bias at room temperature. This device performance based on the quaternary HgMnCdTe shows both theoretical and practical promise of superior performance for wavelengths in the range 1.3 to 1.8 μm for fiber optic applications.

The performance of backside-illuminated HgCdTe/ CdTe photodiode arrays at temperature range of 170- 200K is presented. Electro-optical characterizations of these 3-5 µm detectors show excellent spectral response uniformity (Δλ co = ± 0.03 µm) and high R o A product. Devices with spectral cut off of 4.3 µm at 200K exhibit R o A values of 15 Ω cm2at 200K and 150 Ω cm2at 172K. These values are a factor of 3-5 times higher than the expected R o A for bulk HgCdTe with similar material parameters. The increase is accounted for by the limited diffusion volume configuration obtained by the ∼10 µm thick liquid phase epitaxial active layer. The resulting device structure and performance appears to be well suited for thermoelectrically cooled hybrid focal plane applications.