Ionizing Radiation Total Dose Detectors Using Oligomer Organic Semiconductor Material and Devices

2011 ◽  
Vol 1312 ◽  
Author(s):  
Harshil N. Raval ◽  
V. Ramgopal Rao
Keyword(s):  
Radiation Dose ◽  
Ionizing Radiation ◽  
Total Dose ◽  
Field Effect ◽  
Electrical Measurement ◽  
Organic Electronic Devices ◽  
Total Radiation Dose ◽  
Γ Rays ◽  
Effect Transistor ◽  
Electrical Characterizations

ABSTRACTOrganic semiconducting oligomer – Pentacene, as a material and organic electronic devices based on it, are proposed here as total dose detectors for ionizing radiation. Pentacene, when exposed to ionizing radiation of γ – rays using Cobalt – 60 (60Co) radiation source, shows increase in the conductivity of the material which can be used as a sensing phenomenon for determining the dose of ionizing radiation. The change in material property was also verified using UV-visible (UV-VIS) spectrum for pentacene thin-films with rising absorption peaks at the oxidized positions in the wavelength. A pentacene resistor can be used as a detector, as the change in the conductivity of the pentacene film can be easily quantified by measuring the change in resistance of the pentacene resistor after different total radiation dose exposures. The experiments resulted in a sensitivity of 340 kΩ/Gy for a total 100 Gy radiation dose for the pentacene resistor. Furthermore, employing this simple electrical measurement technique for determining the dose of ionizing radiation and to improve the sensitivity of the sensor by transistor action, a pentacene based organic field effect transistor (OFET) was exposed to ionizing radiation. Change in OFF current (IOFF) of the OFET sensor with W/L = 19350 μm/100 μm, suggests a sensitivity of 21 nA/Gy for 100 Gy dose. Also, changes in various other parameters like threshold voltage, subthreshold swing, field effect mobility, number of interface states etc. can be extracted from the electrical characterizations which prove their usefulness as a detector for ionizing radiation.

Copper (II) Phthalocyanine Based Field Effect Transistors as Total Dose Sensors for Determining Ionizing Radiation Dose

2012 ◽  
Vol 1383 ◽  
Author(s):  
Harshil N. Raval ◽  
V. Ramgopal Rao
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Radiation Dose ◽  
Ionizing Radiation ◽  
Total Dose ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Electronic Devices ◽  
Organic Electronic Devices ◽  
Organic Electronic

ABSTRACTChanges in the material properties of copper (II) phthalocyanine (CuPc) thin-films were studied upon exposure to increasing dose of ionizing radiation using photoluminescence spectrum. We observe generation of new energy states below the band gap upon exposure to ionizing radiation. Organic electronic devices – CuPc based resistor and an organic field effect transistor (OFET) – are proposed in this work as total dose sensors for ionizing radiation. We observe an increase in the conductivity of CuPc thin-films with increasing dose of ionizing radiation. To overcome the possibility of changes/degradation in the electrical properties of CuPc thin-films upon interaction with various gases and moisture in the environment, a passivation layer of silicon nitride, deposited by hot-wire CVD process is proposed. Effect of ionizing radiation on the electrical properties of thin-films of CuPc has been studied. We observe a 170% increase in the resistance of the thin-film for a total of 50 Gy radiation dose using Cobalt-60 (60Co) radiation source. Moreover, significant changes in the electrical characteristics of an OFET, with CuPc as an organic semiconductor, have been observed with increasing doses of ionizing radiation. Experiments with an OFET (W/L = 19350 μm / 100 μm and tox = 150 nm) as a sensor resulted in a ∼100X change in the OFF current for a total of 50 Gy dose of ionizing radiation exhibiting a sensitivity of ∼1 nA/Gy. Moreover, implementing a reader circuit, shift in the threshold voltage of the OFET at 1e-7 A drain current displayed a sensitivity of 80 mV/Gy for a total of 50 Gy dose of ionizing radiation. CuPc based organic electronic devices have advantages as sensors because of their low-cost fabrication, large area coverage on flexible substrates, etc.

Crystal and Electrical Characterizations of EpitaxialCeXZr1-XO2Buffer Layer for the Metal/Ferroelectric/Insulator/Semiconductor Field Effect Transistor

1996 ◽  
Vol 35 (Part 1, No. 9B) ◽  
pp. 5150-5153 ◽  
Author(s):  
Tadahiko Hirai ◽  
Kazuhito Nagashima ◽  
Hiroshi Koike ◽  
Shinya Matsuno ◽  
Yasuo Tarui
Keyword(s):  
Field Effect ◽  
Field Effect Transistor ◽  
Effect Transistor ◽  
Electrical Characterizations

AN ORGANIC FIELD EFFECT TRANSISTORS-BASED SENSING PLATFORM FOR ENVIRONMENTAL/SECURITY APPLICATIONS

2011 ◽  
Vol 10 (04n05) ◽  
pp. 891-898 ◽  
Author(s):  
RAVISHANKAR S. DUDHE ◽  
HARSHIL N. RAVAL ◽  
ANIL KUMAR ◽  
V. RAMGOPAL RAO
Keyword(s):  
Radiation Dose ◽  
Ionizing Radiation ◽  
Organic Semiconductor ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Semiconductor Layer ◽  
Electrical Characteristics ◽  
Organic Field Effect Transistors ◽  
Γ Radiation ◽  
Semiconducting Material

Organic semiconducting material based sensors have been used for various environmental applications. Organic field effect transistors (OFETs) also find their applications in explosive vapor detection and total ionizing radiation dose determination. OFETs using poly 3-hexylthiophene (P3HT), a p-type organic semiconductor material and CuII tetraphenylporphyrin ( CuTPP ) composite as their active material were investigated as sensors for detection of various nitro-based explosive vapors with greater than parts per billion sensitivity range. Significant changes, suitable for sensor response, were observed in ON current (Ion) and transconductance (gm) extracted from electrical characteristics of the OFET after exposure to vapors of various explosive compounds. However, a similar device response was not observed to strong oxidizing agents such as benzoquinone (BQ) and benzophenone (BP). Also, the use of organic semiconducting material sensors for determining total ionizing radiation dose was studied, wherein the conductivity of the material was measured as a function of total ionizing radiation dose. An organic semiconducting material resistor was exposed to γ-radiation and it was observed that the change in resistance was proportional to the ionizing radiation dose. Changes in various parameters extracted from electrical characteristics of the OFET after γ-radiation exposure resulted in an improved sensitivity. To protect the organic semiconductor layer from the degradation in the ambient the sensors were passivated with a thin layer of silicon nitride.

Assessment of Ionizing Radiation Hardness of a GaN Field-Effect Transistor

2019 ◽  
Author(s):  
Alexis C. Vilas Boas ◽  
M. A. A. de Melo ◽  
R. B. B. Santos ◽  
R. C. Giacomini ◽  
N. H. Medina ◽  
...  
Keyword(s):  
Ionizing Radiation ◽  
Field Effect ◽  
Field Effect Transistor ◽  
Radiation Hardness ◽  
Effect Transistor

Novel Dynamic Scanning Microscope Probe and its Application to Local Electrical Measurement in an Ion Sensitive Field Effect Transistor

2004 ◽  
Vol 838 ◽  
Author(s):  
T. Akiyama ◽  
K. Suter ◽  
N. F. de Rooij ◽  
U. Staufer
Keyword(s):  
Scanning Probe Microscopy ◽  
Field Effect ◽  
Field Effect Transistor ◽  
Quartz Tuning Fork ◽  
External Source ◽  
Electrical Measurement ◽  
Scanning Microscope ◽  
Source Current ◽  
Effect Transistor ◽  
Dynamic Scanning

ABSTRACTA unique self-actuating and self-sensing probe, which is based on a quartz tuning fork and a microfabricated cantilever, is presented for dynamic scanning probe microscopy. The probing tip can be electrically connected to an external source or measure unit. The sensitivity of the drain-source current of an ion sensitive field effect transistor (ISFET) was investigated as a function of the probe position in order to assess the potential of the probe in device testing, where its non-optical read-out mechanism may proof to be a particular advantage.

scholarly journals Synthesis of 5,15-A2BC-Type Porphyrins to Modify a Field-Effect Transistor for Detection of Gram-Negative Bacteria

2021 ◽  
Author(s):  
Laurie Neumann ◽  
Keyword(s):  
Field Effect ◽  
Field Effect Transistor ◽  
Gold Surface ◽  
Electrical Measurement ◽  
Fluorescence Lifetime Imaging ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Lifetime Imaging ◽  
Assembled Monolayers ◽  
Effect Transistor

Current biological sensing technologies of bacteria are time consuming, labor intensive and thus expensive. Furthermore, their accuracy and reproducibility could be improved. Conventional electrical measurement methods might combine high sensitive sensing systems with biological requirements. A promising approach is the trapping of bacteria on the surface of the gate-electrode of a modified field-effect transistor (FET) using porphyin based self-assembled monolayers (SAMs). 5,15-A2BC-type porphyrins were synthesized originating from a 5,15-diphenylporphyrin with the functionality to connect to a gold surface. The SAM formation on the surface of the gold electrode was proven by well-established analytical methods. In this work a synthesis route is presented for a linker which is attached to a peptide or cysteine group for trapping of Gram-negative bacteria. Fluorescence lifetime imaging microscopy (FLIM) measurements of porphyrin-stained bacteria were performed to verify the linkage ability.

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