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Development of Low Dark.Current SiGe Near-Infrared PIN Photodetectors on 300 mm Silicon Wafers

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Optics and Photonics Journal 2016年第5期6卷 61-68页

作者： Caitlin Rouse John W. Zeller Harry Efstathiadis Pradeep Haldar Jay S. Lewis Nibir k. Dhar Priyalal Wijewarnasuriya Yash R. Puri ashok k. sood State University of New York.Polytechnic Institute Albany NY USA Magnolia Optical Technologies Inc. Woburn MA USA DARPA/MTO Arlington VA USA US Army Night Vision Sensors and Electronic Division Fort Belvoir VA USA US Army Research Laboratory Adelphi MD USA

SiGe offers a low-cost alternative to conventional infrared sensor material systems such as InGaAs, InSb, and HgCdTe for developing near-infrared (NIR) photodetector devices that do not require cooling and can operate with relatively low dark.current. As a result of the significant difference in thermal expansion coefficients between germanium (Ge) and silicon (Si), tensile strain incorporated into SiGe detector devices through specialized growth processes can extend their NIR wavelength range of operation. We have utilized high throughput, large-area complementary metal-oxide semiconductor (CMOS) technology to fabricate Ge based p-i-n (PIN) detector devices on 300 mm Si wafers. The two-step device fabrication process, designed to effectively reduce the density of defects and dislocations arising during deposition that form recombination centers which can result in higher dark.current, involves low temperature epitaxial deposition of Ge to form a thin p+ seed layer, followed by higher temperature deposition of a thick.r Ge intrinsic layer. Phosphorus was then ion-implanted to create devices with n+ regions of various doping concentrations. Secondary ion mass spectroscopy (SIMS) has been utilized to determine the doping profiles and material compositions of the layers. In addition, electrical characterization of the I-V photoresponse of different devices from the same wafer with various n+ region doping concentrations has demonstrated low dark.current levels (down to below 1 nA at -1 V bias) and comparatively high photocurrent at reverse biases, with optimal response for doping concentration of 5 × 1019 cm-3.

关键词： Photodetectors Infrared Detectors Germanium Photodiodes Large-Area Wafers

Photon orbits and phase transition for Letelier AdS black.holes immersed in perfect fluid dark.matter

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Chinese Physics C 2024年第6期48卷 247-259页

作者： Ashima sood Md Sabir Ali J.k.Singh Sushant G.Ghosh Department of Mathematics Netaji Subhas University of TechnologyNew Delhi-110078India Centre for Theoretical Physics Jamia Millia IslamiaNew Delhi 110025India Department of Physics Mahishadal Raj CollegePurba MedinipurWest Bengal721628India Institute of Theoretical Physics&Research Center of Gravitation Lanzhou UniversityLanzhou 730000China k.y Laboratory of Quantum Theory and Applications of MoE Lanzhou UniversityLanzhou 730000China Lanzhou Center for Theoretical Physics&k.y Laboratory of Theoretical Physics of Gansu Province Lanzhou UniversityLanzhou 730000China Astrophysics and Cosmology Research Unit School of MathematicsStatistics and Computer ScienceUniversity of KwaZulu-NatalPrivate Bag X54001Durban 4000South Africa

We obtain an exact solution for spherically symmetric Letelier AdS black.holes immersed in perfect fluid dark.matter(PFDM).Considering the cosmological constant as the positive pressure of the system and volume as its conjugate variable,we analyze the thermodynamics of our black.holes in the extended phase *** to the back.round clouds of strings parameter(a)and the parameter endowed with PFDM(β),we analyze the Hawk.ng temperature,entropy,and specific ***,we investigate the relationship between the photon sphere radius and phase transition for the Letelier AdS black.holes immersed in *** the analysis,with a particular condition,non-monotonic behaviors are found between the photon sphere radius,impact parameter,PFDM parameter,temperature,and *** can regard the changes in both the photon sphere radius and impact parameter before and after phase transition as the order parameter;their critical exponents near the critical point are equal to the same value,1/2,similar to that in ordinary thermal *** indicates that a universal relation of gravity may exist near the critical point for a black.hole thermodynamic system.

关键词： AdS black.holes perfect fluid dark.matter Letelier spacetime photon orbit extended phase space thermodynamics correlation of photon orbit and thermodynamics

Development of Nanostructured Antireflection Coatings for EO/IR Sensor and Solar Cell Applications

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Materials Sciences and Applications 2012年第9期3卷 633-639页

作者： ashok k. sood Adam W. sood Roger E. Welser Gopal G. Pethuraja Yash R. Puri Xing Yan David J. Poxson Jaehee Cho E. Fred Schubert Nibir k. Dhar Dennis L. Polla Pradeep Haldar Jennifer L. Harvey College of Nanoscale Science and Engineering Albany USA Department of Electrical and Computer Systems Engineering and Physics Rensselaer Polytechnic Institute Troy USA Magnolia Solar Inc. Albany USA Microsystems Technology Office of the Defense Advanced Research Projects Agency Arlington USA New York.State Energy Research and Development Authority Albany USA.

Electro-optical/infrared (EO/IR) sensors and photovoltaic power sources are being developed for a variety of defense and commercial applications. One of the critical technologies that will enhance both EO/IR sensor and photovoltaic module performance is the development of high quality nanostructure-based antireflection coatings. In this paper, we review our work.on advanced antireflection structures that have been designed by using a genetic algorithm and fabricated by using oblique angle deposition. The antireflection coatings are designed for the wavelength range of 250 nm to 2500 nm and an incidence angle between 00 and 400. These nanostructured antireflection coatings are shown to enhance the optical transmission through transparent windows over a wide band of interest and minimize broadband reflection losses to less than one percent, a substantial improvement over conventional thin-film antireflection coating technologies.

关键词： Antireflection Coating Nanostructured Layer Oblique Angle Deposition Silicon Dioxide Broadband Omni-Directional

Current-Voltage Characteristics of ITO/p-Si and ITO/n-Si Contact Interfaces

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Advances in Materials Physics and Chemistry 2012年第2期2卷 59-62页

作者： Gopal G. Pethuraja Roger E. Welser ashok k. sood Changwoo Lee Nicholas J. Alexander Harry Efstathiadis Pradeep Haldar Jennifer L. Harvey College of Nanoscale Science and Engineering Albany USA Magnolia Solar Incorporated Albany USA Magnolia Solar Incorporated Woburn USA New York.State Energy Research and Development Authority Albany USA ollege of Nanoscale Science and Engineering Albany USA

We investigated the electrical contact characteristics of indium tin oxide (ITO)/doped hydrogenated amorphous silicon (a-Si:H) junctions. For efficient collection of photo-generated carriers, photovoltaic and photodetector devices require good ohmic contacts with transparent electrodes. The amorphous-Si thin films were sputter deposited on ITO coated glass substrates. As-deposited p-type a-Si:H on ITO formed nearly ohmic type contacts and further annealing did not improve the contact characteristics. On the other hand, as-deposited n-type a-Si:H on ITO formed an ohmic contact, while further annealing resulted in a Schottk. type contact. The ITO contact with p-type silicon semiconductor is a ro-bust ohmic contact for Si based optoelectronic devices.

关键词： Sputtered Amorphous Silicon Electrical Contact Characteristics ITO/Si Contact

Effect of Ge Incorporation on Bandgap and Photosensitivity of Amorphous SiGe Thin Films

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Materials Sciences and Applications 2012年第2期3卷 67-71页

作者： Gopal G. Pethuraja Roger E. Welser ashok k. sood Changwoo Lee Nicholas J. Alexander Harry Efstathiadis Pradeep Haldar Jennifer L. Harvey 不详

We investigated the structural and optical properties of amorphous-SiGe thin films synthesized via a low-cost, high-growth rate deposition method. Films were formed by e-beam evaporation of mixed pellets of Si and Ge. Film composition was varied by changing the weight ratio of Si and Ge pellets mixture. Films were amorphous with a composition uniform. Ge-rich films are in tensile stress, while Si-rich films are in compressive stress. As the Ge fraction increases (from 22 at.% to 94 at.%), the optical bandgap decreases (from 1.7 eV to 0.9 eV) and the photosensitivity of the films extends into IR band of solar spectrum. By changing the weighted ratio of the evaporation source mixture, the bandgap and optical sensitivity of a-SiGe films can be easily tuned. Our studies prove that a-SiGe films are a tunable absorber. This can be used for photo-detector, photovoltaic and microelectronic applications to extend the spectral response.

关键词： A-Si1–xGex Thin Films Structural Properties Optical Properties Compositional Effect Bandgap Tuning

GUARDIAN: A Multi-Tiered Defense Architecture for Thwarting Prompt Injection Attack. on LLMs

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Journal of Software Engineering and Applications 2024年第1期17卷 43-68页

作者： Parijat Rai Saumil sood Vijay k. Madisetti Arshdeep Bahga School of Computer Science Engineering & Technology Bennett University Greater Noida India School of Cybersecurity and Privacy Georgia Institute of Technology Atlanta USA Cloudemy Technology Labs Chandigarh India

This paper introduces a novel multi-tiered defense architecture to protect language models from adversarial prompt attack.. We construct adversarial prompts using strategies lik. role emulation and manipulative assistance to simulate real threats. We introduce a comprehensive, multi-tiered defense framework.named GUARDIAN (Guardrails for Upholding Ethics in Language Models) comprising a system prompt filter, pre-processing filter leveraging a toxic classifier and ethical prompt generator, and pre-display filter using the model itself for output screening. Extensive testing on Meta’s Llama-2 model demonstrates the capability to block.100% of attack.prompts. The approach also auto-suggests safer prompt alternatives, thereby bolstering language model security. Quantitatively evaluated defense layers and an ethical substitution mechanism represent k.y innovations to counter sophisticated attack.. The integrated methodology not only fortifies smaller LLMs against emerging cyber threats but also guides the broader application of LLMs in a secure and ethical manner.

关键词： Large Language Models (LLMs) Adversarial Attack Prompt Injection Filter Defense Artificial Intelligence Machine Learning Cybersecurity

A randomized controlled trial on triamcinolone versus saline impregnated merocel post endoscopic sinus surgery: Our experience in a tertiary care centre

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世界耳鼻咽喉头颈外科杂志英文版 2024年第3期10卷 193-199页

作者： sood Ananya Goel k.ushboo Bhagat Sanjeev Sahni Dimple k.mar Sharma Dinesh Yadav Vishav Department of Otorhinolaryngology and Head & Neck.Surgery Government Medical College Patiala Punjab India

Purpose: To assess the potential benefit of impregnating Merocel (a non-absorbable nasal dressing) with a topical steroid solution, for use as a direct and slow local delivery system of steroids after sinus surgery to improve postoperative wound ***: In this randomized controlled trial, 40 patients with bilateral chronic rhinosinusitis with nasal polyposis were subjected to functional endoscopic sinus surgery. Following the completion of the surgery, Merocel pack. were inserted in the bilateral nasal cavities and infiltrated with 4 mL triamcinolone (40 mg/mL) in one nasal cavity (treatment group) and 4 mL normal saline in the other (control group). Nasal pack. were removed on the third postoperative day and postoperative healing assessment was done on postoperative Week. 1, 2, 4, and 12. The findings were noted as per Lund k.nnedy (Lk.S) and perioperative sinus endoscopy (POSE) scores and compared on both ***: Significant (P k.nnedy score for crusting and polyp at Week.12, for edema at Week.1, and nasal discharge at Week. 1 and 12, but there was no significant improvement in scarring at any week. Overall, the difference between the treatment and control arms was statistically significant at all postoperative visits except at Week.4. Also, there was a significant improvement in POSE scores at Week. 1, 2, and 12 but not at Week.***: This study positively concludes that the nasal cavity pack.d with drug-soak.d pack. had less scarring and edema in the postoperative period and the overall wound healing was much better as compared to saline-soak.d pack..

关键词： chronic rhinosinusitis functional endoscopic sinus surgery Lund k.nnedy merocele perioperative sinus endoscopy triamcinolone

Anesthetic consideration in Meigs syndrome with large pleural effusion and lung collapse

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Journal of Acute Disease 2024年第1期13卷 43-44,I0006,I0007页

作者： Shalendra Singh Deepak.Mishra Deepu k.Peter Munish sood Department of Anaesthesiology and Critical Care Command Hospital(NC)UdhampurIndia Department of Anaesthesiology and Critical Care Command Hospital(SC)PuneIndia Department of Pulmonary Medicine Command Hospital(NC)UdhampurIndia Department of Orthopaedics INHSMumbaiIndia

Meigs syndrome(MS)is characterized by a benign ovarian tumor(fibroma),hydrothorax on the right side,and ascites;which can be resolved permanently after *** literature reveals that most MS surgeries were performed under general anesthesia(GA)[1].However,GA poses major risk. to the *** the high risk.of gastric content regurgitation,poor general condition or dyselectrolytemia may lead to delayed arousal,and associated multi-organ *** mechanical ventilation is also difficult due to ascites and hydrothorax(reduced cardiac output,impaired ventilation-perfusion in lungs causing hypoxia and hypercapnia)[1,2].In this letter,we report a case of MS tumor resection under the subarachnoid block.SAB)to mitigate these issues and also review the complications associated with both techniques.

关键词： anesthesia impaired ascites

Evaluating Privacy Leak.ge and Memorization Attack. on Large Language Models (LLMs) in Generative AI Applications

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Journal of Software Engineering and Applications 2024年第5期17卷 421-447页

作者： Harshvardhan Aditya Siddansh Chawla Gunik. Dhingra Parijat Rai Saumil sood Tanmay Singh Zeba Mohsin Wase Arshdeep Bahga Vijay k. Madisetti School of Computer Science Engineering & Technology Bennett University Greater Noida India Cloudemy Technology Labs Chandigarh India School of Cybersecurity and Privacy Georgia Institute of Technology Atlanta USA

The recent interest in the deployment of Generative AI applications that use large language models (LLMs) has brought to the forefront significant privacy concerns, notably the leak.ge of Personally Identifiable Information (PII) and other confidential or protected information that may have been memorized during training, specifically during a fine-tuning or customization process. We describe different black.box attack. from potential adversaries and study their impact on the amount and type of information that may be recovered from commonly used and deployed LLMs. Our research investigates the relationship between PII leak.ge, memorization, and factors such as model size, architecture, and the nature of attack. employed. The study utilizes two broad categories of attack.: PII leak.ge-focused attack. (auto-completion and extraction attack.) and memorization-focused attack. (various membership inference attack.). The findings from these investigations are quantified using an array of evaluative metrics, providing a detailed understanding of LLM vulnerabilities and the effectiveness of different attack..

关键词： Large Language Models PII Leak.ge Privacy Memorization Overfitting Membership Inference Attack.(MIA)