A5087915591- Semiconductor Quantum Structures and Devices
- Advancements in Semiconductor Devices and Circuit Design
- Semiconductor materials and devices
- Advanced Semiconductor Detectors and Materials
- Graphene research and applications
- Nanowire Synthesis and Applications
- 2D Materials and Applications
- Silicon Carbide Semiconductor Technologies
- Thin-Film Transistor Technologies
- Carbon Nanotubes in Composites
- Ferroelectric and Negative Capacitance Devices
- Chalcogenide Semiconductor Thin Films
- Quantum and electron transport phenomena
- Silicon and Solar Cell Technologies
- Calibration and Measurement Techniques
- Infrared Target Detection Methodologies
- Advanced Optical Sensing Technologies
- Diamond and Carbon-based Materials Research
- Semiconductor materials and interfaces
- GaN-based semiconductor devices and materials
- Copper Interconnects and Reliability
- Healthcare Facilities Design and Sustainability
- Photonic and Optical Devices
- Advanced MEMS and NEMS Technologies
- Force Microscopy Techniques and Applications
University of Virginia
2017-2024
International Islamic University, Islamabad
2013-2019
Ansys (United States)
2019
Synopsys (United States)
2019
BRAC University
2015
National University of Computer and Emerging Sciences
2013
Stanford University
2007-2010
Purdue University West Lafayette
2007
Digital alloy and random Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.85</sub> Ga xmlns:xlink="http://www.w3.org/1999/xlink">0.15</sub> As xmlns:xlink="http://www.w3.org/1999/xlink">0.56</sub> Sb xmlns:xlink="http://www.w3.org/1999/xlink">0.44</sub> avalanche photodiodes (APDs) exhibit low excess noise, comparable to Si APDs. Consequently, this material is a promising multiplication layer candidate for separate absorption, charge,...
The InGaAs lattice-matched to InP has been widely deployed as the absorption material in short-wavelength infrared photodetection applications such imaging and optical communications. Here, a series of digital alloy (DA)-grown InAs/GaAs short-period superlattices were investigated extend spectral range. scanning transmission electron microscopy, high-resolution X-ray diffraction, atomic force microscopy measurements exhibit good quality, while photoluminescence (PL) spectra demonstrate wide...
Digital alloy Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.85</sub> Ga xmlns:xlink="http://www.w3.org/1999/xlink">0.15</sub> As xmlns:xlink="http://www.w3.org/1999/xlink">0.56</sub> Sb xmlns:xlink="http://www.w3.org/1999/xlink">0.44</sub> , random and xmlns:xlink="http://www.w3.org/1999/xlink">0.79</sub> In xmlns:xlink="http://www.w3.org/1999/xlink">0.21</sub> xmlns:xlink="http://www.w3.org/1999/xlink">0.74</sub>...
The unprecedented wide bandgap tunability (∼1 eV) of AlxIn1-xAsySb1-y lattice-matched to GaSb enables the fabrication photodetectors over a range from near-infrared mid-infrared. In this paper, valence band-offsets in with different Al compositions are analyzed by tight binding calculations and X-ray photoelectron spectroscopy measurements. observed weak variation band offsets is consistent lack any minigaps band, compared conduction band.
Abstract Avalanche photodiodes fabricated from AlInAsSb grown as a digital alloy exhibit low excess noise. In this article, we investigate the band structure‐related mechanisms that influence impact ionization. Band‐structures calculated using an empirical tight‐binding method and Monte Carlo simulations reveal mini‐gaps in conduction do not inhibit electron Good agreement between full measured noise characteristics is demonstrated. image
Graphene Nanoribbon (GNR) and Carbon Nanotube (CNT) are currently being considered as two of the most promising options to replace silicon technology. Silicon technology is faced with scaling limits other material issues which hinder development transistor In this paper, effect relative dielectric constant on performances ballistic schottky barrier field-effect (GNRFET) (CNTFET) studied a comparative analysis between transistors provided. It has been observed that using gate higher leads...
We present a quasi-analytical model for Tunnel Field Effect Transistors (TFETs) that includes the microscopic physics and chemistry of interfaces non-idealities. The ballistic band-to-band tunneling current is calculated by modifying well known Simmons equation oxide tunneling, where we integrate Wentzel-Kramers-Brillouin (WKB) over transverse modes. extend to finite temperature non-rectangular barriers using two-band channel material an analytical potential profile obtained from Poisson's...
A series of $I\phantom{\rule{0}{0ex}}I\phantom{\rule{0}{0ex}}I\ensuremath{-}V$ alloy-based avalanche photodiodes are recently seen to demonstrate superior performance such as low excess noise, but the origin behavior is not completely understood. The authors use atomistic modeling material and transport properties deconstruct underlying physical mechanisms, which attributed a combination engineered minigaps, increased effective mass, spin-orbit coupling. These attributes selectively limit...
Energy efficiency in digital circuits is limited by the subthreshold swing (SS), which defines how abruptly a transistor switches between its ON and OFF-states. The SS particularly important for targeting minimum-energy computation operate region OFF-states of transistor. MOSFET devices fundamentally thermionic emission, has inspired search new whose can reach below Boltzmann thermal limit. Tunnel field-effect transistors (TFETs) have emerged as post-CMOS candidate with low (steep) been...
III-V material based digital alloy Avalanche Photodiodes (APDs) have recently been found to exhibit low noise similar Silicon APDs. The materials can be chosen operate at any wavelength in the infrared spectrum. In this work, we present a physics-based SPICE compatible compact model for APDs built from parameters extracted an Environment-Dependent Tight Binding (EDTB) calibrated ab-initio Density Functional Theory (DFT) and Monte Carlo (MC) methods. Using approach, accurately capture...
Currently, the advancement of silicon transistor technology is being hindered by different issues such as scaling limits. It has become imperative to replace existing with new continue MOSFETs. Thus, materials and production techniques are studied laboriously trend set Moore's Law. The graphene nanoribbon (GNR) carbon nanotube (CNT) two promising that can in future A study been conducted effect relative dielectric constant on device performances a ballistic Schottky barrier GNR field‐effect...
With the advancement of silicon technology having culminated to a point where scaling limitations transistors have manifested themselves as being unavoidable, experimentation with Graphene Nanoribbon and Carbon Nanotube field effect has become utmost importance. In this paper gate oxide thickness on performances ballistic Schottky barrier transistor (GNRFET) (CNTFET) is studied. A comparative analysis also done two kinds FETs based thickness. It been observed that lowering increases on-state...
Some III-V digital alloy avalanche photodiodes exhibit low excess noise. These alloys have hole ionization coefficients due to presence of small 'minigaps', enhanced effective mass and large separation between light-hole split-off bands in the valence band. In this letter, an explanation for formation minigaps using a tight binding picture is provided. Furthermore, we demonstrate that decreasing substrate lattice constant can increase minigap size transport direction. This leads reduced...
The digital alloy (DA) growth technique has been widely reported to implement band structure engineering for deterministic optical and electronic properties overcome limitations imposed by miscibility gaps. Random (RA) InGaAs lattice-matched InP with a bandgap of 0.74 eV is used as the absorption material photodetectors in short-wavelength infrared spectral range. In this work, grown on substrates alloy, short-period InAs/GaAs superlattices, six monolayer periodic thickness extend its...
A theoretical calculation of impact ionization using quantum transport is pre-sented here. An atomistic matrix Hamiltonian in real space, capable capturing complex mass tensors heterostructures, combined with Non-equilibrium Green’s functions a self-consistent Born approximation for Coulomb interactions between electrons and holes.
Digital alloy APDs have recently demonstrated superior performance. This superiority is attributed to the presence of minigaps in digital alloys. We study different alloys and their possible impact on APD
A scalable, low cost, power, and small footprint uncooled mid-wave infrared (MWIR) sensing technology capable of measuring thermal dynamics with high spatial resolution can be great benefit to space satellite applications such as remote earth observation. Conventional photodetectors designed absorb MWIR band wavelengths have often been based on HgCdTe material typically require cooling. However, through integration bilayer graphene functioning a mobility channel in photodetectors, higher...
Recent experimental investigations in Bi-Layer Graphene (BLG) have shown interesting and useful electrical behavior that can be leveraged building novel device applications. One such being carrier multiplication effects within the BLG. We propose to use a heterostructure of BLG-CdTe-HgCdTe as detector structure marries this effect along with unique bandalignment which suggest an Ohmic contact for electrons but Schottky barrier holes. Using dissipative quantum transport model, namely...