Novel Metal-Semiconductor-Metal Photodetectors on Semi-Insulating Indium Phosphide

1996 ◽  
Vol 448 ◽  
Author(s):  
J.W. Palmer ◽  
W.A. Anderson
Keyword(s):  
Indium Tin Oxide ◽  
Dark Current ◽  
Antireflection Coating ◽  
Hole Trapping ◽  
Relative Transparency ◽  
Transit Times ◽  
Metal Semiconductor Metal ◽  
The Difference ◽  
Lift Off ◽  
Inp Substrates

AbstractDepositing Pd or Au on InP at substrate temperatures near 77K has previously been found to significantly reduce the interaction between the metal and semiconductor upon formation of the interface. In this work, this technique was used to fabricate metal-semiconductor-metal photodetectors (MSMPD’s) on semi-insulating (SI) InP substrates with superior characteristics compared to detectors formed using standard room temperature (RT) metal deposition. The low-temperature (LT) metallizations were patterned using a polyimide/SiO2 lift-off mask, and a SiO antireflection coating was used to attain near-zero reflection at λ=840nm. The detectors had an active area of 200μm × 200μm, and line widths and line spacings of 3μm. Detectors having a LT-Pd/SI-InP structure had a dark current of 80nA at 5V, which was a factor of 4 lower than the dark current of conventional MSMPD’s. Additionally, LT-Pd/SI-InP MSMPD’s exhibited excellent saturation characteristics and a responsivity of 0.75 A/W. Detectors with an indium-tin-oxide (ITO)/LT-Au(200Å)/SI-InP structure had a higher responsivity of 1.0 A/W, due to the relative transparency of this metallization. In contrast, MSMPD’s with RT metallizations had poor saturation characteristics, consistent with the results of others. The difference in the illuminated characteristics of MSMPD’s with RT and LT metallizations was due to a change in the internal photoconductive gain mechanism. In RT detectors, hole trapping at interface states near the cathode dominated the gain mechanism. In LT detectors, the difference in carrier transit-times dominated.

Integrated MSM-FET Photoreceiver Fabricated on Mocvd Grown Hg1-xCdxTe

1990 ◽  
Vol 216 ◽  
Author(s):  
Patrick W. Leech ◽  
Peter J. Gwynn ◽  
Geoffrey N. Pain ◽  
Novica R. Petkovic ◽  
James Thompson ◽  
...  
Keyword(s):  
Dark Current ◽  
Field Effect Transistor ◽  
Gaas Substrates ◽  
Integrated Devices ◽  
Metal Semiconductor Metal ◽  
Initial Work ◽  
Effect Transistor ◽  
Lift Off ◽  
Msm Photodetectors ◽  
Photoconductive Detector

ABSTRACTWe report on progress in the monolithic integration of a metal-semiconductor-metal (MSM) detector and transimpedence amplifier and of a photoconductive detector (PCD) with a metal-semiconductor field effect transistor (MESFET) in Hg1-xCdxTe. The layers of CdTe/n-type Hg1-xCdxTe were grown by MOCVD on semi-insulating GaAs substrates (2° misoriented 100). Fabrication of the devices was by an FET planar process; with a standard lift-off used to form Schottky metallization on both the interdigitated electrodes of the MSM detector (2μm width, 2μm spacing) and the gate of the MESFETs (5μm length, 100μm width). The MSM photodetectors exhibited breakdown voltages in the range 60 to 80V, a dark current of 1 Ona at 5V bias, and responsivities of > 1.0 A/W measured at 40V using CW 1.3um illumination. The integrated devices have been characterised by electrical and micro RBS techniques; the results were found to be strongly dependent on the stoichiometric x ratio of the Hg1-xCdxTe. This initial work demonstrates the suitability of Hg1-xCdxTe/GaAs structures in the fabrication of integrated optoelectronic circuits.

Epitaxial lift-off GaAs/AlGaAs metal-semiconductor-metal photodetectors with back passivation

1993 ◽  
Vol 5 (10) ◽  
pp. 1210-1212 ◽  
Author(s):  
M.C. Hargis ◽  
R.E. Carnahan ◽  
J.S. Brown ◽  
N.M. Jokerst
Keyword(s):  
Metal Semiconductor Metal ◽  
Lift Off

Validation of cerebral arteriovenous malformation hemodynamics assessed by DSA using quantitative magnetic resonance angiography: preliminary study

2017 ◽  
Vol 10 (2) ◽  
pp. 156-161 ◽  
Author(s):  
Sophia F Shakur ◽  
Denise Brunozzi ◽  
Ahmed E Hussein ◽  
Andreas Linninger ◽  
Chih-Yang Hsu ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Magnetic Resonance Angiography ◽  
Transit Time ◽  
Internal Carotid ◽  
Flow Measurements ◽  
Quantitative Magnetic Resonance ◽  
Transit Times ◽  
Before And After ◽  
Preliminary Study ◽  
The Difference

BackgroundThe hemodynamic evaluation of cerebral arteriovenous malformations (AVMs) using DSA has not been validated against true flow measurements.ObjectiveTo validate AVM hemodynamics assessed by DSA using quantitative magnetic resonance angiography (QMRA).Materials and methodsPatients seen at our institution between 2007 and 2016 with a supratentorial AVM and DSA and QMRA obtained before any treatment were retrospectively reviewed. DSA assessment of AVM flow comprised AVM arterial-to-venous time (A-Vt) and iFlow transit time. A-Vt was defined as the difference between peak contrast intensity in the cavernous internal carotid artery and peak contrast intensity in the draining vein. iFlow transit times were determined using syngo iFlow software. A-Vt and iFlow transit times were correlated with total AVM flow measured using QMRA and AVM angioarchitectural and clinical features.Results33 patients (mean age 33 years) were included. Nine patients presented with hemorrhage. Mean AVM volume was 9.8 mL (range 0.3–57.7 mL). Both A-Vt (r=−0.47, p=0.01) and iFlow (r=−0.44, p=0.01) correlated significantly with total AVM flow. iFlow transit time was significantly shorter in patients who presented with seizure but A-Vt and iFlow did not vary with other AVM angioarchitectural features such as venous stenosis or hemorrhagic presentation.ConclusionsA-Vt and iFlow transit times on DSA correlate with cerebral AVM flow measured using QMRA. Thus, these parameters may be used to indirectly estimate AVM flow before and after embolization during angiography in real time.

Effect of a static magnetic field onEscherichia coliadhesion and orientation

2016 ◽  
Vol 62 (11) ◽  
pp. 944-952 ◽  
Author(s):  
Lotfi Mhamdi ◽  
Nejib Mhamdi ◽  
Naceur Mhamdi ◽  
Philippe Lejeune ◽  
Nicole Jaffrezic ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Bacterial Adhesion ◽  
Parallel Magnetic Field ◽  
Field Orientation ◽  
Static Magnetic Fields ◽  
Preliminary Study ◽  
The Difference ◽  
The Magnetic Field

This preliminary study focused on the effect of exposure to 0.5 T static magnetic fields on Escherichia coli adhesion and orientation. We investigated the difference in bacterial adhesion on the surface of glass and indium tin oxide-coated glass when exposed to a magnetic field either perpendicular or parallel to the adhesion surface (vectors of magnetic induction are perpendicular or parallel to the adhesion surface, respectively). Control cultures were simultaneously grown under identical conditions but without exposure to the magnetic field. We observed a decrease in cell adhesion after exposure to the magnetic field. Orientation of bacteria cells was affected after exposure to a parallel magnetic field. On the other hand, no effect on the orientation of bacteria cells was observed after exposure to a perpendicular magnetic field.

scholarly journals Suppression of dark current in GeO_x-passivated germanium metal-semiconductor-metal photodetector by plasma post-oxidation

2015 ◽  
Vol 23 (13) ◽  
pp. 16967 ◽  
Author(s):  
Jian Kang ◽  
Rui Zhang ◽  
Mitsuru Takenaka ◽  
Shinichi Takagi
Keyword(s):  
Dark Current ◽  
Metal Semiconductor Metal

2. Adhesion of the plasma-polymerized fluorocarbon films to silicon substrates The adhesion properties of the plasma-polymerized FC coatings were determined by using a test, already employed by Yasuda and Sharma [13] (see Fig. 1 and Table 1) in which the silicon substrates coated with plasma FC-films were boiled in a0.9% sodium chloride solution. The FC thin films produced in the processes 1 and 2 were lifted after a very short time (15 minutes). Coatings generated in process 3 were lifted after the second cycle of boiling. The films produced in processes 4 and 5 withstood the complete test procedure. The results are shown in Fig. 3. The poor adhesion of the polymerized films in the first two processes is due to the fact that these processes do not involve a plasma pre-treatment process. The difference between processes 1 and 3 is only in the plasma pre-treatment (process 1 does not contain the pre-treatment step of the silicon surface). The fluorocarbon films deposited by processes 4 and 5 have shown the best adhesion. These test results indicate that the plasma pre-treatment is very important and necessary for a good adhesion of the FC coatings to the silicon surfaces. 2.3. Patterning of FC films 2.3.1. Patterning through resist mask. The patterning of the FC films through a photoresist mask (conventional All resist AR-P351) was examined after deposition for process No. 5. Different coating parameters were investigated to improve the adhesion of the resist to the FC surface. The best adhesion results were obtained using the process parameters, shown in Table 3. Differences in the thickness uniformity of so-deposited resists were in a range below 5%. The samples were etched in a pure oxygen plasma in an RIE-system after the lithography steps (pre-bake, exposure, development, post-bake). A resolution of 2 /xm was obtained. A significant increase in the surface energy was not observed after resist stripping. The sessile contact angle of water was 103°. 2.3.2. Lift-off process for patterning thin plasma polymerized FC films. A lift-off process was also examined to pattern the thin FC films. The lithography steps were used before the plasma polymerization process was carried out (Fig. 2). A standard resist AR-P351 was coated directly onto the Si substrates. After all lithography

2014 ◽  
pp. 275-278
Keyword(s):  
Treatment Process ◽  
Test Procedure ◽  
Silicon Surfaces ◽  
Silicon Substrates ◽  
Fluorocarbon Films ◽  
Si Substrates ◽  
Complete Test ◽  
The Difference ◽  
Pre Treatment ◽  
Lift Off

Analysis of screw dislocation mediated dark current in Al0.50Ga0.50N solar-blind metal-semiconductor-metal photodetectors

2018 ◽  
Vol 498 ◽  
pp. 35-42 ◽  
Author(s):  
Shashwat Rathkanthiwar ◽  
Anisha Kalra ◽  
Rangarajan Muralidharan ◽  
Digbijoy N. Nath ◽  
Srinivasan Raghavan
Keyword(s):  
Screw Dislocation ◽  
Dark Current ◽  
Metal Semiconductor Metal ◽  
Solar Blind

Arterial hematocrit and separation of cells and plasma in the dog kidney

1964 ◽  
Vol 207 (1) ◽  
pp. 128-132 ◽  
Author(s):  
Francis P. Chinard ◽  
Theodore Enns ◽  
Mary F. Nolan
Keyword(s):  
Blood Flow ◽  
Volume Of Distribution ◽  
Human Albumin ◽  
Indicator Dilution ◽  
Regression Equations ◽  
Dilution Technique ◽  
Transit Times ◽  
Dog Kidney ◽  
The Mean ◽  
The Difference

With the indicator-dilution technique, the mean transit times of cells (tr) labeled with Cr51 and of plasma (tpl) labeled with T-1824 or as human albumin-I131 decrease as the arterial hematocrit (Hct) decreases. The regression equations are: tr = 0.0388 Hct + 1.73 and tpl = 0.0596 Hct + 1.69. The separation of cells and plasma labels, as measured by the difference of the mean transit times (Δt), is also related to the hematocrit. Δt = 0.00895 Hct + 0.269. There is an excess plasma label volume of distribution per 100 g kidney, ΔVpl, which may be intra- or extravascular. ΔVpl = QrΔt (1 - Hct), where Qr is blood flow per 100 g kidney. ΔVpl is independent of tr and of Hct. However, ΔVpl increases with Qr. ΔVpl = 0.127 Qr + 1.79. The hypothesis that the separation of cells and plasma results from transcapillary passage of the plasma labels is consistent with but is not established by the data.

Transit time dispersion in the pulmonary arterial tree

1998 ◽  
Vol 85 (2) ◽  
pp. 565-574 ◽  
Author(s):  
Anne V. Clough ◽  
Steven T. Haworth ◽  
Christopher C. Hanger ◽  
Jerri Wang ◽  
David L. Roerig ◽  
...  
Keyword(s):  
Transit Time ◽  
Mean Transit Time ◽  
Arterial Tree ◽  
Lung Lobe ◽  
Transit Times ◽  
Pulmonary Capillary ◽  
Time Dispersion ◽  
Pulmonary Arterial ◽  
The Difference ◽  
In Transit

Knowledge of the contributions of arterial and venous transit time dispersion to the pulmonary vascular transit time distribution is important for understanding lung function and for interpreting various kinds of data containing information about pulmonary function. Thus, to determine the dispersion of blood transit times occurring within the pulmonary arterial and venous trees, images of a bolus of contrast medium passing through the vasculature of pump-perfused dog lung lobes were acquired by using an X-ray microfocal angiography system. Time-absorbance curves from the lobar artery and vein and from selected locations within the intrapulmonary arterial tree were measured from the images. Overall dispersion within the lung lobe was determined from the difference in the first and second moments (mean transit time and variance, respectively) of the inlet arterial and outlet venous time-absorbance curves. Moments at selected locations within the arterial tree were also calculated and compared with those of the lobar artery curve. Transit times for the arterial pathways upstream from the smallest measured arteries (200-μm diameter) were less than ∼20% of the total lung lobe mean transit time. Transit time variance among these arterial pathways (interpathway dispersion) was less than ∼5% of the total variance imparted on the bolus as it passed through the lung lobe. On average, the dispersion that occurred along a given pathway (intrapathway dispersion) was negligible. Similar results were obtained for the venous tree. Taken together, the results suggest that most of the variation in transit time in the intrapulmonary vasculature occurs within the pulmonary capillary bed rather than in conducting arteries or veins.

Surface Passivation and the Ultrafast Optical Response of Low-Temperature-Grown GaAs

1995 ◽  
Vol 378 ◽  
Author(s):  
H. H. Wang ◽  
J. F. Whitaker ◽  
K. Al-Hemyari ◽  
S. L. Williamson
Keyword(s):  
Low Temperature ◽  
Dark Current ◽  
Surface Passivation ◽  
Surface States ◽  
Time Response ◽  
Temporal Response ◽  
Dc Voltage ◽  
Ultrafast Optical ◽  
Metal Semiconductor Metal ◽  
Low Temperature Grown Gaas

AbstractMetal-semiconductor-metal photodetectors fabricated using low-temperature-grown GaAs have been passivated using AlGaAs cap layers in order to understand the influence of surface states and fields on the properties of these detectors. It has been found that passivation has little effect on the time response or persistent photoconductive tails associated with the detectors, but that responsivity and dark current can be enhanced in certain circumstances. The dependence of the temporal response on optical fluence and dc-voltage bias were observed for both passivated and unpassivated detectors.

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