A5071485197- Semiconductor Quantum Structures and Devices
- Nanowire Synthesis and Applications
- Advanced Semiconductor Detectors and Materials
- Semiconductor materials and devices
- Silicon Nanostructures and Photoluminescence
- Ion-surface interactions and analysis
- Chalcogenide Semiconductor Thin Films
- Physics of Superconductivity and Magnetism
- Thin-Film Transistor Technologies
- GaN-based semiconductor devices and materials
- Semiconductor materials and interfaces
- Integrated Circuits and Semiconductor Failure Analysis
- Semiconductor Lasers and Optical Devices
- Electronic and Structural Properties of Oxides
- Photonic and Optical Devices
- Advancements in Semiconductor Devices and Circuit Design
- Silicon and Solar Cell Technologies
- Magnetic and transport properties of perovskites and related materials
- Quantum optics and atomic interactions
- Quantum Dots Synthesis And Properties
- Nonlinear Photonic Systems
- Superconductivity in MgB2 and Alloys
- Advanced NMR Techniques and Applications
- ZnO doping and properties
- Terahertz technology and applications
Solid State Physics Laboratory
2007-2024
University of Delhi
2021
Indian Institute of Technology Delhi
2001-2002
University of Electro-Communications
2001-2002
Indian Institute of Technology Indore
2000
Confinement effects on first-order and second-order Raman scattering in nanocrystalline silicon are presented. The average dimension of the nanocrystals has been determined by an analysis spectra using phenomenological phonon confinement model. acoustic bands 2LA 2TA do not seem to be influenced similar those bulk. optic broadened shifted comparison ratio integrated intensities $I{(2\mathrm{T}\mathrm{O})}_{\mathrm{int}}/I{(\mathrm{TO})}_{\mathrm{int}}$ depends upon nanocrystal size varies...
A comparative study of the temperature-dependent Raman scattering nanocrystalline and bulk silicon is presented. The samples were made by a cw laser annealing process, characteristic dimensions determined with phenomenological phonon confinement model. Experimental results indicate higher degree anharmonicity in nanocrystals compared to that bulk. anharmonic constants are found be highly size dependent increase greatly decreasing dimensions. lifetimes have two contributions, one temperature...
Abstract Zinc telluride (ZnTe) epitaxial layers were grown on gallium arsenide (GaAs) (211) substrate at different growth temperatures by molecular beam epitaxy. The fabricated interdigitated metal semiconductor configuration-based photodetector (PD) ZnTe exhibited a stable and excellent photo response in broad spectral range (250–550 nm) up to 125 °C. room temperature higher (125 °C) values of maximum current, responsivity detectivity an applied bias 5 V 550 nm wavelength 3.5 × 10 −8 A, 0.1...
This paper presents a theoretical investigation of the phase-sensitive modulation instability continuous or quasicontinuous probe beam in an asymmetric coupled quantum well (ACQW) system facilitated by electromagnetically induced transparency. The dispersive properties can be controlled not only Rabi frequency control field but relative phase between them as well. ACQW exhibits large Kerr and quintic nonlinearities which could controlling beam. is unstable, gain bandwidth unstable...
Magnetic field dependence of transport critical current density ( J c ) a polycrystalline YBCO superconductor in cooled and zero cases have been studied experimentally. The measured value when the sample was (FC) always larger than that for (ZFC) case same magnetic field. We also observe (i) peak ratio FC to ZFC (ii) an anomalous rise with increasing These observations are explained as signature two types regions (intergrain intragrain) sintered specimens.
Oblique incidence polarized IR reflectivity measurements of Metal Organic Chemical Vapor Deposition (MOCVD) grown GaN epitaxial layers on sapphire are discussed in the context recent literature Berreman effect. The dependence p-polarized spectrum angle and thickness films is analyzed theoretically results compared with experiment. “Berreman minimum” that minimum near longitudinal-optical (LO) phonon frequency shown to be due optical interference. Our calculations show greater than 0.1 μm for...
In this report, the precise alignment of catalyst free InAs nanowires (NWs) on pre-patterned Au microelectrodes by dielectrophoresis (DEP) technique for gas sensing applications is presented. The NWs have been grown Si (111) substrate molecular beam epitaxy (MBE) technique. effect dispersing solvents, electrode geometries and gaps, magnitude, frequency duration applied voltage etc, has studied aligning DEP Current–voltage (I–V) measurements aligned show linear behavior at room temperature...
Mesoporous structures with interconnecting nano-fibers (MSINs) are realized by irradiating low energy (50, 75, and 100 keV) beams of Ar <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> -ions normal to the surface molecular beam epitaxially grown gallium antimonide (GaSb) epi-layer deposited on (100) oriented semi-insulating arsenide (GaAs) substrates. The irradiation keV -ion at fluence 1 × 10...
We present a detailed study on the influence of several growth related factors such as indium segregation, spacer layer thickness and Si δ doping structural, optical electrical properties molecular beam epitaxy grown pseudomorphic high electron mobility transistor (P-HEMT) structures. Simulation resolution x-ray diffraction (HRXRD) rocking curve was performed compared with experimental data to determine quantum well (QW) composition segregation changes in QW composition. It is shown that...
This paper reports two specific aspects of Si implantation in the molecular beam epitaxy grown p-type GaSb epilayer, namely, evolution nanoporosity and doping characteristics. The is done with 100 keV ions at four different fluences, i.e., 5 × 1013, 1 1014, 1015 ions/cm2. A field-emission scanning electron microscope (in-plane cross-sectional view) shows a smooth nanoporous pore diameter 10–20 nm for higher fluences. thickness porous film enhanced from 235 (fluence: 1014 ions/cm2) to 515...
This paper presents formation of interconnected mesoporous structure using low energy (50 keV) Ar+-ion irradiation normal to the GaSb surface for ion fluence 1 × 1016 and 5 1017 ions/cm2. The morphology pristine irradiated samples was observed field emission scanning electron microscopy (FE-SEM) atomic force (AFM). Depth profile distribution cascade collisions with track in epi-layer were simulated stopping range matter-transport matter (SRIM-TRIM) simulation. Presence oxide phases such as...
We present surface photo-voltage (SPV) measurements on molecular beam epitaxy (MBE) grown single quantum well (SQW) laser structures. Each layer in the hetero-structure has been identified by measurement of SPV signal after a controlled sequential chemical etching process. These results have correlated with high resolution x-ray diffraction and photoluminescence (PL) measurements. Quantum confined Stark effect carrier screening electric field taken into consideration both theoretically...
<p class="p1"> </p><p class="p2"><span class="s1"> </span>Microstructural and compositional characterisation of electronic materials in support the development GaAs, GaN, GaSb based multilayer device structures is described. Electron microscopy techniques employing nanometer sub-nanometer scale imaging capability structure chemistry have been widely used to characterise various aspects optoelectronic such as InGaAs quantum dots, pseudomorphic (pHEMT),...
A comparative study for the pristine and sulfur passivated surfaces of gallium antimonide (GaSb) grown using molecular beam epitaxy is presented with results recorded through X-ray photoelectron spectroscopy (XPS) atomic force microscopy (AFM) techniques. The as-grown GaSb were treated separately 20% aqueous ammonium sulphide, ((NH4)2S), at 60°C 10 m, sodium sulfide nonahydrate (Na2S.9H2O) molarity 1 4 m room temperature base-thioacetamide (base-TAM) 0.18 40 70°C. AFM topography shows...