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Pathak DK, Rani C, Sati A, Kumar R. Developments in Raman Spectromicroscopy for Strengthening Materials and Natural Science Research: Shaping the Future of Physical Chemistry. ACS PHYSICAL CHEMISTRY AU 2024; 4:430-438. [PMID: 39346605 PMCID: PMC11428286 DOI: 10.1021/acsphyschemau.4c00017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 05/14/2024] [Accepted: 05/15/2024] [Indexed: 10/01/2024]
Abstract
Spectroscopic techniques, especially Raman spectroscopy, cover a large subset in the teaching and research domain of physical chemistry. Raman spectroscopy, and other Raman based techniques, establishes itself as a powerful analytical tool with diverse applications across scientific, industrial, and natural science (including biology and pharmacy) fields and helps in the progress of physical chemistry. Recent advancements and future prospects in Raman spectroscopy, focusing on key areas of innovation and potential directions for research and development, have been highlighted here along with some of the challenges that need to be addressed to prepare Raman based techniques for the future. Significant progress has been made in enhancing the sensitivity, spatial resolution, and time resolution of Raman spectroscopy techniques. Raman spectroscopy has applications in all areas of research but especially in biomedical applications, where Raman spectroscopy holds a great promise for noninvasive or minimally invasive diagnosis, tissue imaging, and drug monitoring. Improvements in instrumentation and laser technologies have enabled researchers to achieve higher sensitivity levels, investigate smaller sample areas with improved spatial resolution, and capture dynamic processes with high temporal resolution. These advancements have paved the way for a deeper understanding of molecular structure, chemical composition, and dynamic behavior in various materials and biological systems. It is high time that we consider whether Raman based techniques are ready to be improved based on the strength of the current era of AI/ML and quantum technology.
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Affiliation(s)
- Devesh K Pathak
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Chanchal Rani
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Aanchal Sati
- Department of Physics, Hukum Singh Bora Govt PG College, Soban Singh Jeena University Almora, Someshwar 263637, India
| | - Rajesh Kumar
- Department of Physics, Indian Institute of Technology Indore, Simrol, Indore 453552, India
- Centre for Advanced Electronics, Indian Institute of Technology Indore, Simrol, Indore 453552, India
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Kumar C, Kashyap V, Escrig J, Shrivastav M, Kumar V, Guzman F, Saxena K. The dopant (n- and p-type)-, band gap-, size- and stress-dependent field electron emission of silicon nanowires. Phys Chem Chem Phys 2024; 26:17609-17621. [PMID: 38864309 DOI: 10.1039/d4cp00825a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2024]
Abstract
This study investigates the electron field emission (EFE) of vertical silicon nanowires (Si NWs) fabricated on n-type Si (100) and p-type Si (100) substrates using catalyst-induced etching (CIE). The impact of dopant types (n- and p-types), optical energy gap, crystallite size and stress on EFE parameters has been explored in detail. The surface morphology of grown SiNWs has been characterized by field emission scanning electron microscopy (FESEM), showing vertical, well aligned SiNWs. Optical absorption and Raman spectroscopy confirmed the presence of the quantum confinement (QC) effect. The EFE performance of the grown nanowire arrays has been examined through recorded J-E measurements under the Fowler-Nordheim framework. The Si NWs grown on p-type Si showed a minimum turn-on field and also a higher field enhancement factor. The band-bending diagram also suggests a lower barrier height of p-type Si NWs compared to n-type Si NWs, which plays a key role in enhancing the EFE performance. These investigations suggest that dopant types (n- and p-types), band gap, crystallite size and stress influence the EFE parameters and Si NWs grown on p-type Si (100) substrates are much more favorable for the investigation of EFE properties.
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Affiliation(s)
- Chandra Kumar
- Departamento de Física, Universidad de Santiago de Chile (USACH), Avda. Víctor Jara 3493, 9170124 Santiago, Chile
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), 9170124 Santiago, Chile
| | - Vikas Kashyap
- Department of Physics, Panjab University, Chandigarh, 160014, India
| | - Juan Escrig
- Departamento de Física, Universidad de Santiago de Chile (USACH), Avda. Víctor Jara 3493, 9170124 Santiago, Chile
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), 9170124 Santiago, Chile
| | - Monika Shrivastav
- Department of Physics, Malaviya National Institute of Technology, Jaipur, India
| | - Vivek Kumar
- Department of Physics, Indian Institute of Information Technology Design and Manufacturing, Kancheepuram, Chennai 600127, India
| | - Fernando Guzman
- Departamento de Física, Facultad de Ciencias, Universidad Católica del Norte, Avenida Angamos 0610, Casilla 1280, Antofagasta, Chile
| | - Kapil Saxena
- Department of Applied Sciences, Kamla Nehru Institute of Technology, Sultanpur, 228118, Uttar Pradesh, India
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Rani C, Tanwar M, Ghosh T, Kandpal S, Pathak DK, Maximov MY, Kumar R. Parallel or interconnected pores’ formation through etchant selective silicon porosification. CAN J CHEM 2021. [DOI: 10.1139/cjc-2021-0190] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The effect of the oxidizer present in the etching solution on the surface morphology and microstructure obtained after porosifying a p-type silicon wafer using metal-assisted chemical etching was studied. The morphologies of Si wafers porosified using two different solutions, HF/H2O2 and HF/KMnO4, were compared to establish how either of the oxidizers (H2O2 or KMnO4) should be chosen depending on the desired application. A comparative study revealed that parallel pores with wire-like structures or interconnected pores with cheese-like structures can be obtained when H2O2 or KMnO4 are chosen, respectively. Careful analysis of the SEM images was carried out using ImageJ to establish that the samples prepared using KMnO4 are more porous due to aggressive etching. Additionally, experimental and theoretical Raman spectroscopic studies have been utilized to study the presence of low-dimensional Si nanostructures, which are a few nanometers in size, at the microscopic level in porosified silicon.
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Affiliation(s)
- Chanchal Rani
- Materials and Device Laboratory, Department of Physics, Indian Institute of Technology Indore, Simrol 453552, India
| | - Manushree Tanwar
- Materials and Device Laboratory, Department of Physics, Indian Institute of Technology Indore, Simrol 453552, India
| | - Tanushree Ghosh
- Materials and Device Laboratory, Department of Physics, Indian Institute of Technology Indore, Simrol 453552, India
| | - Suchita Kandpal
- Materials and Device Laboratory, Department of Physics, Indian Institute of Technology Indore, Simrol 453552, India
| | - Devesh K. Pathak
- Materials and Device Laboratory, Department of Physics, Indian Institute of Technology Indore, Simrol 453552, India
| | - Maxim Yu Maximov
- Peter the Great Saint-Petersburg Polytechnic University, Saint Petersburg 195221, Russia
| | - Rajesh Kumar
- Materials and Device Laboratory, Department of Physics, Indian Institute of Technology Indore, Simrol 453552, India
- Centre for Indian Scientific Knowledge Systems, Indian Institute of Technology Indore, Simrol 453552, India
- Centre for Advanced Electronics, Indian Institute of Technology Indore, Simrol 453552, India
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Tanwar M, Pathak DK, Chaudhary A, Krylov AS, Pfnür H, Sharma A, Ahn B, Lee S, Kumar R. Pseudo-Anomalous Size-Dependent Electron-Phonon Interaction in Graded Energy Band: Solving the Fano Paradox. J Phys Chem Lett 2021; 12:2044-2051. [PMID: 33606540 DOI: 10.1021/acs.jpclett.1c00217] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Quantum size effects on interferons (electron-phonon bound states), confined in fractal silicon (Si) nanostructures (NSs), have been studied by using Raman spectromicroscopy. A paradoxical size dependence of Fano parameters, estimated from Raman spectra, has been observed as a consequence of longitudinal variation of nanocrystallite size along the Si wires leading to local variations in the dopants' density which actually starts governing the Fano coupling, thus liberating the interferons to exhibit the typical quantum size effect. These interferons are more dominated by the effective reduction in dopants' density rather than the quantum confinement effect. Detailed experimental and theoretical Raman line shape analyses have been performed to solve the paradox by establishing that the increasing size effect actually is accompanied by receding Fano coupling due to the weakened electronic continuum. The latter has been validated by observing a consequent variation in the Raman signal from dopants which was found to be consistent with the above conclusion.
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Affiliation(s)
- Manushree Tanwar
- Materials and Device Laboratory, Discipline of Physics, Indian Institute of Technology Indore, Simrol 453552, India
| | - Devesh K Pathak
- Materials and Device Laboratory, Discipline of Physics, Indian Institute of Technology Indore, Simrol 453552, India
| | - Anjali Chaudhary
- Materials and Device Laboratory, Discipline of Physics, Indian Institute of Technology Indore, Simrol 453552, India
| | - Alexander S Krylov
- Kirensky Institute of Physics, Federal Research Center KSC SB RAS Krasnoyarsk 660036, Russia
| | - Herbert Pfnür
- Institut für Festkörperphysik, Leibniz Universität Hannover, Appelstr. 2, D-30167 Hannover, Germany
| | - Ashutosh Sharma
- Department of Materials Science and Engineering, Ajou University, Suwon 16499, Korea
| | - Byungmin Ahn
- Department of Materials Science and Engineering, Ajou University, Suwon 16499, Korea
- Department of Energy Systems Research, Ajou University, Suwon 16499, Korea
| | - Sangyeob Lee
- Department of Materials Science and Engineering, Hanbat National University, Daejeon 34158, Korea
| | - Rajesh Kumar
- Materials and Device Laboratory, Discipline of Physics, Indian Institute of Technology Indore, Simrol 453552, India
- Centre for Advanced Electronics, Indian Institute of Technology Indore, Simrol 453552, India
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