Improved Electrical Property of Sb-Doped SnO2 Nanonets as Measured by Contact and Non-Contact Approaches

Junpeng Lu ,  Liu Hongwei ,  Sun Cheng ,  Zheng Minrui ,  Lim Kim Yong ,  Nirpan Mathews ,  Subodh G. Mhaisalkar ,  Tang Sing Hai,  Zhang Xinhai and Sow Chorng Haur

RSC Adv., 2012, Accepted Manuscript

DOI: 10.1039/C2RA20973J

Abstract

This work reports the characterization of antimony doping effect on the electron transportation in SnO2 nanonets via a contact (field-effect transistor) and a non-contact (terahertz time-domain spectroscopy) approach. The doping influence is well demonstrated by the contact method through exploring the output characteristics of the devices. In addition, through the analysis of the terahertz time-domain spectra using Drude-Smith model, the non-contact method provides more precise characterization ascribed to the absence of extra effects such as contact resistance and nanowire-nanowire junction barriers.

....... The transmission terahertz spectra were carried out using a conventional THz-TDS system (TeraView Spectra 3000). The 100 fs optical pulses centered at 800 nm with repetition rate of 76 MHz ...

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Hybrid SRRs Design and Fabrication for Broadband Terahertz Metamaterials

Pan, Z.Y. Zhang, P. ; Chen, Z.C. ; Vienne, G. ; Hong, M.H.

IEEE Photonics Journal 4(5), 1267 – 1272, (2012)

Data Storage Inst., Agency for Sci., Technol. & Res. (A*STAR), Singapore, Singapore

ABSTRACT

Hybrid metamaterials comprising split-ring resonator (SRR) structures with different gap dimensions are fabricated on polyethylene naphthalate (PEN) films by parallel laser micro-lens array (MLA) lithography and a liftoff process. The unit cell of hybrid metamaterials consists of four SRRs with the same SRR core side length but different gap sizes. The different-gap-size SRRs in each unit cell correspond to different but successive resonance dips, which are coupled to form a significantly broader band with enhanced resonance. The hybrid SRRs design is numerically and experimentally demonstrated, showing a much broader bandwidth to cover all narrowband induced by each SRR and enhanced resonance as compared with a uniform SRR design.

......The pitch p of the samples is defined by the pitch size of the MLA, which is fixed at 100 m. The sample characterization is carried out with a THz time-domain spectroscopy (THz-TDS) system (TPS3000, Teraview Inc.) in ..


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Terahertz Imaging for Margin Assessment of Breast Cancer Tumors

Ahmed M. Hassan1, David C. Hufnagle2, Magda El-Shenawee1 and Gilbert E. Pacey3,4

1Department of Electrical Engineering, University of Arkansas, Fayetteville, AR 72701 

2Department of Chemistry and Biochemistry, Miami University, Oxford, OH, 45056 

3Ohio Wright Center for Innovation, IDCAST, Dayton, OH 45402

4University of Dayton Research Institute, Dayton, OH 45469

Abstract 

This work presents experimental terahertz measurements of excised formalin fixed paraffin embedded (FFPE) human breast cancer tissues. The data are collected using a terahertz pulsed system operating from 0.1 THz to 3THz. The results represent preliminary investigation of terahertz imaging technique for assessing the tumor margins. The direct imaging method will be compared with inverse scattering imaging methods using the experimental data along with histopathological images as references.

for full paper see http://emag.eleg.uark.edu/conference/2012_IMS_THz_margins.pdf

-------The THz imaging setup was conducted using the system TPI Imaga 1000 (Teraview Ltd). The TPI system utilizes a time domain THz ----------

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Investigating Tautomeric Polymorphism in Crystalline Anthranilic Acid Using Terahertz Spectroscopy and Solid-State Density Functional Theory

Sean P. Delaney , Ewelina M. Witko , Tiffany M. Smith , and Timothy M. Korter *

Department of Chemistry, Syracuse University, 1-014 Center for Science and Technology, Syracuse, New York 13244-4100, United States

J. Phys. Chem. A, 2012, 116 (30), pp 8051–8057

DOI: 10.1021/jp303961w

 

Abstract

Terahertz spectroscopy is sensitive to the interactions between molecules in the solid-state and recently has emerged as a new analytical tool for investigating polymorphism. Here, this technique is applied for the first time to the phenomenon of tautomeric polymorphism where the crystal structures of anthranilic acid (2-aminobenzoic acid) have been investigated. Three polymorphs of anthranilic acid (denoted Forms I, II and III) were studied using terahertz spectroscopy and the vibrational modes and relative polymorph stabilities analyzed using solid-state density functional theory calculations augmented with London dispersion force corrections. Form I consists of both neutral and zwitterionic molecules and was found to be the most stable polymorph as compared to Forms II and III (both containing only neutral molecules). The simulations suggest that a balance between steric interactions and electrostatic forces is responsible for the favoring of the mixed neutral/zwitterion solid over the all neutral or all zwitterion crystalline arrangements.

Note by Blogger: Professor Tim Korter continues his excellent work at Syracuse University in the understanding of the terahertz spectrum of materials.

Precise dielectric spectroscopy of a dual-frequency nematic mixture over a broad temperature range

P. Perkowskia*, M. Mrukiewicza, K. Garbata, M. Laskaa, U. Chodorowa, W. Pieceka, R. Dąbrowskia & J. Parkaa

DOI:

10.1080/02678292.2012.714483

Abstract

W1832A, a dual-frequency, multi-component nematic mixture prepared at the Military University of Technology, was investigated by means of dielectric spectroscopy over a wide frequency range (100 Hz–10 MHz) and over a wide temperature range (−60°C–100°C). At the temperature of −60°C it is still a nematic. The investigated mixture changes the sign of dielectric anisotropy at temperature and frequency domains. High-precision dielectric spectroscopy studies of molecular motions (around short (S) and long (L) molecular axes) were performed using cells of 5 μm thickness. Gold electrodes in measuring cells were spin-coated with agents for homogenous and homeotropic alignments. In the low-temperature region these motions are hindered enough to observe intra-molecular motions, which typically (at room temperature) are observed in THz frequency range of the measuring field. S molecular motion is eliminated from the measurement range at temperatures below −15°C, while L mode is still observed at −60°C. Dielectric spectroscopy results were compared with THz spectroscopy at room temperature.

.......we obtain n ∞O = 1.67 and n ∞E = 1.84. To verify these values we performed refractive indices measurements for the W1832A mixture via THz spectroscopy using a TDS spectrometer Teraview TPS 3000. .......

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TERAVIEW CLEARED FOR WORLD FIRST CANCER PROBE

Tuesday, 10 July 2012 12:21 TONY QUESTED

TERAVIEW CLEARED FOR WORLD FIRST CANCER PROBE

TeraView, the Cambridge UK pioneer and leader in terahertz technology, has been cleared by regulators to start trials of a world-first, hand-held breast cancer probe.

With support from the Technology Strategy Board and in collaboration with surgeons at Guy’s Hospital in London, TeraView has developed the device as part of the world’s first commercial terahertz medical unit.

The research unit is capable of imaging a wide range of tissues and is designed to allow developments to move seamlessly through in-vitro, ex vivo and into in vivo studies.

TeraView has received approval by the Medicines and Healthcare products Regulatory Agency (MHRA) to conduct in-vivo clinical trials for biomedical research using its Terahertz Pulsed Imaging solution.

The trial at Guy’s is focused on the use of Terahertz as an intra-operative probe for the detection of cancer tissue during breast cancer surgery.

If successful, the trial will help surgeons better identify and enable accurate removal of cancer tissue in the breast, reduce second operation rates, improve clinical outcomes and reduce costs.

TeraView CEO Don Arnone said: “We are very pleased to have started the in-vivo trials. We have now been working in this area for over 10 years and it is very exciting to see the fruits of our efforts.

“This application of the technology has the potential to significantly improve clinical outcomes, reduce patient stress and reduce operational costs.”

Terahertz technology allows high-resolution subsurface imaging of tissue. It combines macroscopic and microscopic imaging that potentially allows the precise margin delineation of cancer tissue.

Due in part to its ability to recognise spectral fingerprints, TPI™ provides good contrast between different types of soft tissue, and is a sensitive means of detecting the degree of water content as well as other cancer markers.

TeraView’s proprietary TPI™ software is able to convert such molecular markers into 3D images and in so doing aid surgeons in differentiating between cancerous and non-cancerous tissues.

“This is an important development in the journey of our research into the application of terahertz technology in cancer patients and we are excited about the prospect of commencing the first clinical trial in breast cancer patients” said Arnie Purushotham, professor of breast cancer and consultant surgeon at Guy’s & St Thomas NHS Foundation Trust.

from http://www.businessweekly.co.uk/biomedtech-/14270-teraview-cleared-for-world-first-cancer-probe-