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Fabrication of GaN nano-towers based self-powered UV photodetector

Lalit Goswami, Neha Aggarwal, Pargam Vashishtha, Shubhendra Kumar Jain, Shruti Nirantar, Jahangeer Ahmed, M. A. Majeed Khan, Rajeshwari Pandey, Govind Gupta
2021 Scientific Reports  
AbstractThe fabrication of unique taper-ended GaN-Nanotowers structure based highly efficient ultraviolet photodetector is demonstrated. Hexagonally stacked, single crystalline GaN nanocolumnar structure (nanotowers) grown on AlN buffer layer exhibits higher photocurrent generation due to high quality nanotowers morphology and increased surface/volume ratio which significantly enhances its responsivity upon ultraviolet exposure leading to outstanding performance from the developed detection
more » ... ce. The fabricated detector display low dark current (~ 12 nA), high ILight/IDark ratio (> 104), fast time-correlated transient response (~ 433 µs) upon ultraviolet (325 nm) illumination. A high photoresponsivity of 2.47 A/W is achieved in self-powered mode of operation. The reason behind such high performance could be attributed to built-in electric field developed from a difference in Schottky barrier heights will be discussed in detail. While in photoconductive mode, the responsivity is observed to be 35.4 A/W @ − 3 V along with very high external quantum efficiency (~ 104%), lower noise equivalent power (~ 10–13 WHz−1/2) and excellent UV–Vis selectivity. Nanotower structure with lower strain and dislocations as well as reduced trap states cumulatively contributed to augmented performance from the device. The utilization of these GaN-Nanotower structures can potentially be useful towards the fabrication of energy-efficient ultraviolet photodetectors.
doi:10.1038/s41598-021-90450-w pmid:34035437 fatcat:aueads53ozgcdfmslksvvaj5ve

Oxygen vacancies induced photoluminescence in $$\hbox {SrZnO}_2$$ nanophosphors probed by theoretical and experimental analysis

Manju, Megha Jain, Saibabu Madas, Pargam Vashishtha, Parasmani Rajput, Govind Gupta, Mousumi Upadhyay Kahaly, Kemal Özdoğan, Ankush Vij, Anup Thakur
2020 Scientific Reports  
We report, for the first time, the influence of oxygen vacancies on band structure and local electronic structure of $$\hbox {SrZnO}_2$$ SrZnO 2 (SZO) nanophosphors by combined first principle calculations based on density functional theory and full multiple scattering theory, correlated with experimental results obtained from X-ray absorption and photoluminescence spectroscopies. The band structure analysis from density functional theory revealed the formation of new energy states in the
more » ... den gap due to introduction of oxygen vacancies in the system, thereby causing disruption in intrinsic symmetry and altering bond lengths in SZO system. These defect states are anticipated as origin of observed photoluminescence in SZO nanophosphors. The experimental X-ray absorption near edge structure (XANES) at Zn and Sr K-edges were successfully imitated by simulated XANES obtained after removing oxygen atoms around Zn and Sr cores, which affirmed the presence and signature of oxygen vacancies on near edge structure.
doi:10.1038/s41598-020-74436-8 pmid:33060718 pmcid:PMC7567121 fatcat:g6llojmf7bfvvgz2milfzjccsi

Investigating the growth of AlGaN/AlN heterostructure by modulating the substrate temperature of AlN buffer layer

Neha Aggarwal, Shibin Krishna, Lalit Goswami, Shubhendra Kumar Jain, Akhilesh Pandey, Abhiram Gundimeda, Pargam Vashishtha, Jasveer Singh, Sandeep Singh, Govind Gupta
2021 SN Applied Sciences  
AbstractWe have investigated the impact of AlN buffer layer growth parameters for developing highly single crystalline AlGaN films. The low mobility of Al adatoms and high temperature for compound formation are amongst the major causes that affects the growth quality of AlGaN films. Thus, proper optimization need to be carried out for achieving high quality AlGaN due to an augmented tendency of defect generation compared to GaN films. Thus, growth conditions need to be amended to maximize the
more » ... corporation ability of adatoms and minimize defect density. So, this study elaborates the growth optimization of AlGaN/AlN/Si (111) heterostructure with varied AlN buffer growth temperature (760 to 800 °C). It was observed that the remnant Al in low temperature growth of AlN buffer layer resist the growth quality of AlGaN epitaxial films. A highly single crystalline AlGaN film with comparatively lowest rocking curve FWHM value (~ 0.61°) and smooth surface morphology with least surface defect states was witnessed when AlN buffer was grown at 780 °C. From the Vegard's law, the photoluminescence analysis unveils Aluminium composition of 31.5% with significantly reduced defect band/NBE band ratio to 0.3. The study demonstrates good crystalline quality AlGaN film growth with Aluminium content variation between ~ 30–39% in AlGaN/AlN heterostructure on Si(111) substrate leading to a bandgap range which is suitable for next-generation solar-blind photodetection applications.
doi:10.1007/s42452-021-04274-4 fatcat:grmyqdpjgnbyhnpr4nsp7jcxle

South Asian Declaration—Consensus Guidelines for COVID-19 Vaccination in Cancer Patients

Raja Thirumalairaj, Purvish M. Parikh, Amit Agarwal, Randeep Singh, Arvind Krishnamurthy, Sharad S. Desai, Amita Maheshwari, Prashant Mehta, Abdul Ghafur, S. P. Somashekhar, Ahamed Iqbal, Dhairyasheel N. Savant (+24 others)
2021 South Asian Journal of Cancer  
AbstractWe provide the South Asian Declaration, containing the consensus guidelines for coronavirus disease 2019 (COVID-19) vaccination in cancer patients.
doi:10.1055/s-0041-1731909 fatcat:rhkrfay62vfp7h3mx6pn7n27jy

Development of Ni-Sn/Al2O3Nano Catalyst Powders Using Solution Combustion Synthesis for H2 Production from Biomass by Aqueous Phase Reforming

Shubhi Vashishtha, Govind Manglani, Banasri Roy
Innovative Trends in Applied Physical, Chemical, Mathematical Sciences and Emerging Energy Technology for Sustainable Development   unpublished
Different catalysts are being investigated worldwide for efficient hydrogen production from biomass. Raney Ni-Sn is reported to be one of the best catalyst systems for hydrogen production by aqueous phase reforming [1]. However, high specific surface area-to-volume ratio and precise design of pore structure combined with proper control of acidity/basicity of the support oxide are very important factors for high catalytic performance. Solution combustion synthesis (SCS) is an efficient technique
more » ... to synthesize highly porous nano particle size pure ceramics[2,3]. In this work, we report preparation and characterization of nano Ni-Sn/Al2O3 catalysts using SCS method. Two set of samples have been designed; in the first one, the metal/support catalyst is directly prepared via one pot combustion, while for the other one, Al2O3 support is prepared first and then metal is loaded by standard wet impregnation. Aluminum nitrate, nickel nitrate and stannous chloride are combined in appropriate ratio collectively to act as oxidizer, while glycine is used as the fuel. Fig. 1 summarizes steps of catalysts preparation. Investigations regarding the structure and properties are being carried out through characterization techniques including TGA, FTIR and XRD. Phase composition, chemistry, and microstructure of the catalysts will be reported in detail.

Effect of Parenting Style, Academic Environment and Gender on Feeling of Security-Insecurity in Adolescents

Nidhi Malik, Pushpendra Rao upadhyay, Dr. A.C. Vashishtha
2015 International Journal of Indian Psychology  
The Security-insecurity scale: Security-insecurity scale (Hindi version) originally was constructed by Govind Tiwari. This scale consisting a total 70 items including positive and negative.  ... 
doi:10.25215/0202.006 fatcat:nvkwa6myaff5jn6vbqryzno3zq


Prof Vikas Sharma, Sadma
2021 Research journal of english  
In The Three Mistakes of My Life the author reveals the personality of Vidya, Govind Patel, Ishan, Omi, Ali etc. through the conscious mind of Govind ⎯ What does he think of his father?  ...  Govind remarks .His God made him pay a big price in life, but he still felt grateful to him.  ... 
doi:10.36993/rjoe.2020.0111 fatcat:ule26d5h7jh6fcuoeodn6smlzm

Impact of Mixed Farming on Nitrate Contamination in Ground Water in Dausa Tehsil

Abhishek Vashishtha
2018 unpublished
Conclusion Through the about data and discussion is can be concluded that the contamination of nitrate in the ground water in Nangal Govind, Hingotia, Jirota Khurd, Bhandana, Chavandera, malagwas, Khuri  ...  junior chemist public health Engineering Department Laboratory Dausa Name of Villages No. of Samples NO3 Concentration (mg/l) Average NO3 Concentration (mg/L) 1 Dhigaria 02 1, 1 1 2 Nangal Govind  ... 


2020 Procedia Computer Science  
. . . . . . . . . . . . . . . . . . . . 459 Load Balanced Node Clustering scheme using Improved Memetic Algorithm based Meta-heuristic Technique for Wireless Sensor Network Vrajesh Kumar Chawra, and Govind  ...  Mudi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1363 Inferring Sentiments from Supervised Classification of Text and Speech cues using Fuzzy Rules Srishti Vashishtha,  ... 
doi:10.1016/s1877-0509(20)30921-2 fatcat:xnxj5wtx5fcnvl4ekervontxve

Table of Contents

2021 2021 5th International Conference on Trends in Electronics and Informatics (ICOEI)  
Jayalakshmi 44 Smart Solar Portable Power Supply System for Emergency Medical Equipments Govind Sreekumar, Vignesh Chekkichalil, Anamala Oshmitha, Aparna S Nair, Rajasree S.  ...  Technology in Big Data Analytics Rutuja Laxmikant Kolhe, Anuya Joshi, Prachi Vikas Mate, Deeksha Satyendra Gupta, Dipti Patil 1727 Deep Learning based Weather Forecast: A Prediction Sachin Soni, Kuldeep Vashishtha  ... 
doi:10.1109/icoei51242.2021.9452892 fatcat:7brqazsyzzd67fr5pc4ybcdcsu

Conference Main Schedule

2021 2021 International Conference on Intelligent Technologies (CONIT)  
Vashishtha Mutation-based Arithmetic Optimization Algorithm for Global Optimization 4.30 PM 4.45 PM 4 144 Ayesha Gulrajani, Jay Bendre, Vignesh Pillai and Asha Bharambe Relevium -Disaster  ...  Manjula Pattnaik 2 104 Keerthana M, Vishnu Prasath M S and Yaswanthkumar S K A Computer Vision Approach for Automated Driver Assistance System 4.15 PM 4.30 PM 3 110 Sumika Chauhan and Govind  ... 
doi:10.1109/conit51480.2021.9498269 fatcat:6kqyrpvszjcyjjfretndzzdpfy

Changing Imaginaries of Geographies and Journeys in Kumaun & Tibet

Vasudha Pande, Humboldt-Universität Zu Berlin, Humboldt-Universität Zu Berlin
Govind Chatak argues that in the Ramola Gathas, Krishna is a rasik (passionate hero). He says that the erotic aspect dominates these stories and sexual gratification is the desired goal.  ...  Eventually, Vashishtha was initiated into the Mahacinachara by Buddha himself. This involved the worship of Nilogratara who was born on the lake called Cola on the western side of Mount Meru. A.  ... 
doi:10.18452/20995 fatcat:j23umceoiffujpylj6qed7a6bm

Rapporteur's Report on Slow Growth Crops: Coarse Cereals, Oilseeds and Pulses

Prem S. Vashishtha
2002 unpublished
., Govind Pal, and Lakshmanan discuss problems relating to marketing and processing of pulses in different states. All papers use micro-level data to examine the issue.  ...  In fact, this is also observed by Govind Pal for Chandauli district, Uttar Pradesh, Yadav et al. for Haryana, Lakshmanan for Erode district, Tamil Nadu and Tilekar et al. for Osmanabad district, Maharashtra  ... 
doi:10.22004/ag.econ.297906 fatcat:yynujz6jgbgfjktx44jzccmsxe

Spontaneous Urinary Bladder Leiomyoma in a Rhesus Macaque (Macaca mulatta)

Kathleen E Scott, Galit Frydman, James G Fox, Vasudevan Bakthavatchalu
2018 Comparative medicine  
Tu, Shui Ping; Quante, Michael; Bhagat, Govind; Takaishi, Shigeo; Cui, Guanglin; Yang, Xiang D ...  ...  Vashishtha, Malini; Ng, Christopher W; Yildirim, Ferah; Gipson, Theresa A; Kratter, Ian H; Boda ...  ... 
doi:10.30802/aalas-cm-17-000050 pmid:29857795 fatcat:y4zz4lcpbrclphlcwrsh2dp6tm

Haḍimbā Becoming Herself: A Himalayan Goddess in Change

Ehud Halperin
Govind: Like water and oil(Govind, near Haḍimbā temple, April 6, 2011, note 3).Thakur, to take a final example, a villager in his late forties, expressed a more complex view.  ...  On meeting Bhimsen, the medial Pāṇḍava, she attained divinity" (Vashishtha 1996: 128, my translation) . 67 M.R.  ... 
doi:10.7916/d8n30412 fatcat:3em4nbnqpnc53lwimpmn2pt2vi
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