Article
Optics
Zelu Wang, Yingjie Liu, Zi Wang, Yilin Liu, Jiangbing Du, Qinghai Song, Ke Xu
Summary: Extending the optical communication wavelengths to 2 μm can significantly increase data capacity. The ultra-broadband power splitter on silicon demonstrated in this work has a bandwidth exceeding 520 nm from 1500 to 2020 nm. With a triple tapered Y-junction and subwavelength grating structure, the device shows an ultra-compact footprint of only 3 μm x 2 μm and is capable of operating over a broadband from 1.55 μm and 2 μm wavelengths.
Article
Computer Science, Information Systems
Amer Kotb, Kyriakos E. Zoiros
Summary: This paper investigates the use of K-shaped compact silicon waveguides operated at the 1.55 mu m wavelength to demonstrate various basic optical logic operations. The suggested waveguide achieves higher contrast ratios and a speed of approximately 120 Gb/s.
Article
Chemistry, Multidisciplinary
Shaurya Arya, Yunrui Jiang, Byung Ku Jung, Yalun Tang, Tse Nga Ng, Soong Ju Oh, Kenji Nomura, Yu-Hwa Lo
Summary: In this study, a compact and easy-to-use model for colloidal quantum dot (CQD) devices is developed. By considering the properties of quantum dots, ligand binding, and the heterointerface between quantum dots and the electron transport layer, the model can accurately describe and optimize the performance of CQD devices.
Article
Engineering, Electrical & Electronic
Hosni Ajlani, Abdullah Alhumaidi Alotaibi, Sattam R. Alotaibi, Mohamed Karim Azizi
Summary: This study investigates the transmission properties of a multilayer structure operating at 1.55 and 1.53 μm telecom wavelengths. The results show that adjusting the graphene Fermi energy can correct shifts in the working frequency induced by temperature and oxidation of porous silicon (PS).
OPTICAL AND QUANTUM ELECTRONICS
(2021)
Article
Physics, Multidisciplinary
Amer Kotb, Kyriakos E. Zoiros, Wei Li
Summary: The paper presents the use of silicon-on-silica waveguides to realize a complete family of logic gates, including XOR, AND, OR, NOT, NOR, NAND, and XNOR, operated at 1.55 μm. These waveguides consist of three identical slots and six microring resonators, all made of silicon patterned on silica. The gates' principle of operation is based on constructive and destructive interference induced by the phase difference between the input signals. The performance of the gates is evaluated using the contrast ratio (CR) metric, with the proposed waveguides achieving higher CRs and speeds up to 120 Gb s(-1) compared to existing waveguides.
Article
Nanoscience & Nanotechnology
Hengyang Xiang, Mahima Chaudhary, Charlotte Tripon-Canseliet, Zhuoying Chen
Summary: A novel approach was proposed to develop microwave photoconductive switches functional in the short-wave-infrared spectrum window by directly depositing solution-processed colloidal upconversion nanocrystals onto low-temperature-grown gallium arsenide (LT-GaAs). The hybrid upconversion Er3+-doped NaYF4 nanocrystal/LT-GaAs photoconductive switch showed a more than 2-fold increase in the ON/OFF ratio compared to the control device, with a maximum value of 20.6 dB at an input signal frequency of 20 MHz.
Article
Engineering, Electrical & Electronic
Byoungnam Park
Summary: The study quantified the ZnO/PbSe contact resistance for the first time and showed that treatment with ammonium sulfide can enhance interfacial charge transfer rate and decrease contact resistivity. The removal of ligands led to an increase in carrier concentration in the contact region, mitigating carrier depletion.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2022)
Article
Physics, Multidisciplinary
J. Corrigan, J. P. Dodson, H. Ekmel Ercan, J. C. Abadillo-Uriel, Brandur Thorgrimsson, T. J. Knapp, Nathan Holman, Thomas McJunkin, Samuel F. Neyens, E. R. MacQuarrie, Ryan H. Foote, L. F. Edge, Mark Friesen, S. N. Coppersmith, M. A. Eriksson
Summary: This study reports quantum control of eight different transitions in a silicon-based quantum dot, revealing a dense set of energy levels with characteristic spacing far smaller than the single-particle energy, which is argued to arise from Wigner-molecule physics.
PHYSICAL REVIEW LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Matthias J. Grotevent, Claudio U. Hail, Sergii Yakunin, Dominik Bachmann, Michel Calame, Dimos Poulikakos, Maksym V. Kovalenko, Ivan Shorubalko
Summary: Colloidal quantum dot graphene phototransistors with spectral sensitivity up to 3 μm, specific detectivities of 6 x 10(8) Jones at a wavelength of 2.5 μm and 80K temperature are presented. Even at kHz light modulation frequencies, specific detectivities exceed 10(8) Jones, making them suitable for fast video imaging. The simple device architecture and QD film patterning, combined with broad spectral sensitivity, represent an important step toward low-cost, multi-color infrared cameras.
Article
Chemistry, Analytical
Amer Kotb, Kyriakos E. Zoiros, Antonios Hatziefremidis, Chunlei Guo
Summary: Silicon photonics has made significant progress in terms of device functionality, performance, and circuit integration in the past decade. In this study, we theoretically demonstrate a complete family of all-optical logic gates (AOLGs) using finite-difference-time-domain simulations. The proposed compact silicon-on-silica optical waveguides operate at 1.55 μm and show improved contrast ratios (CRs) and higher speeds compared to other designs. These findings suggest that AOLGs can be realized affordably and meet the requirements of lightwave circuits and systems.
Article
Chemistry, Physical
Y. Q. Huang, N. Kang
Summary: Interfacing graphene with other low-dimensional materials has attracted attention recently due to its potential for new physics and device innovations. In this study, colloidal quantum dots (CQDs) were introduced to a bilayer graphene device using a solution-processed approach. The presence of the CQDs drastically altered the magnetotransport properties of the graphene device, leading to the observation of AB-like oscillation in the quantum Hall regime and screening of intervalley scattering. This study demonstrates the potential of this flexible method for engineering microscopic scattering processes and improving the performance of graphene devices.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2024)
Article
Optics
Jianfei Liao, Yuan Xie, Tianye Huang, Zhuo Cheng
Summary: This paper presents a subwavelength-grating-assisted 1 x 2 deWMUX based on the principle of multimode interference, successfully outputting 1.55 and 2 µm wavelengths from two different channels. The simulation results demonstrate that the designed deWMUX has high contrast, low insertion loss, and wide 1 dB bandwidth at both wavelengths. Additionally, manufacturing tolerances of the device are also studied in the paper.
Article
Chemistry, Analytical
Amer Kotb, Kyriakos E. Zoiros, Chunlei Guo
Summary: In this study, a complete set of basic Boolean logic operations is implemented using compact psi-shaped silicon-on-silica optical waveguides at a 1.55 mu m wavelength. The logic gates operate based on interference effects resulting from phase differences of input optical beams and their performance is evaluated using the contrast ratio (CR) metric.
Article
Multidisciplinary Sciences
Ke Wang, Gang Xu, Fei Gao, He Liu, Rong-Long Ma, Xin Zhang, Zhanning Wang, Gang Cao, Ting Wang, Jian-Jun Zhang, Dimitrie Culcer, Xuedong Hu, Hong-Wen Jiang, Hai-Ou Li, Guang-Can Guo, Guo-Ping Guo
Summary: Hole-spin qubits in germanium show promise for rapid, all-electrical qubit control. The authors demonstrate ultrafast single-spin manipulation in a hole-based double quantum dot in a germanium hut wire, with a record Rabi frequency exceeding 540 MHz. These results suggest the potential for ultrafast coherent control of hole spin qubits to meet the requirements for scalable quantum information processing.
NATURE COMMUNICATIONS
(2022)
Article
Multidisciplinary Sciences
Bokang Hou, Michael Thoss, Uri Banin, Eran Rabani
Summary: Electron transfer is a fundamental process, and researchers have demonstrated how to control the transition from nonadiabatic to adiabatic electron transfer in colloidal quantum dot molecules. By changing the neck dimensions and/or quantum dot sizes, the electronic coupling can be tuned, leading to coherent electron transfer even at high temperatures. The study also identifies the modes that strongly influence the charge transfer dynamics.
NATURE COMMUNICATIONS
(2023)
Article
Physics, Applied
Dip Joti Paul, Arjuman Ara Mimi, Arnab Hazari, Pallab Bhattacharya, Md Zunaid Baten
JOURNAL OF APPLIED PHYSICS
(2019)
Article
Physics, Applied
Anthony Aiello, Yuanpeng Wu, Zetian Mi, Pallab Bhattacharya
APPLIED PHYSICS LETTERS
(2020)
Article
Physics, Applied
Kunook Chung, Ayush Pandey, Tuba Sarwar, Anthony Aiello, Zetian Mi, Pallab Bhattacharya, Pei-Cheng Ku
APPLIED PHYSICS LETTERS
(2020)
Article
Optics
Mahitosh Biswas, Ravinder Kumar, Arka Chatterjee, Yuanpeng Wu, Zetain Mi, Pallab Bhattacharya, Samir Kumar Pal, Subhananda Chakrabarti
JOURNAL OF LUMINESCENCE
(2020)
Article
Nanoscience & Nanotechnology
Ankit Udai, Anthony Aiello, Tarni Aggarwal, Dipankar Saha, Pallab Bhattacharya
Summary: This study investigated the femtosecond carrier and photon dynamics in self-organized In0.27Ga0.73N/GaN QDs grown by molecular beam epitaxy. The unique phenomenon in the dynamics is attributed to the contrast in carrier density caused by the different effective masses of carriers.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Physics, Condensed Matter
Tarni Aggarwal, Ankit Udai, Debashree Banerjee, Vikas Pendem, Shonal Chouksey, Pratim Saha, Sandeep Sankaranarayanan, Swaroop Ganguly, Pallab Bhattacharya, Dipankar Saha
Summary: The ultrafast nonlinear carrier-photon dynamics of GaN-based optoelectronic devices with nanostructures are studied, focusing on the impact of excited-state dynamics on device performance. Experimental and theoretical research shows the importance of understanding carrier and photon dynamics in these nanostructures.
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
(2021)
Article
Nanoscience & Nanotechnology
Tarni Aggarwal, Ankit Udai, Pratim K. Saha, Swaroop Ganguly, Pallab Bhattacharya, Dipankar Saha
Summary: Efficiency droop at high carrier-injection regimes is a concern in InGaN/GaN quantum-confined hetero-structure-based light-emitting diodes (LEDs). This study demonstrates a potential solution through the positive effects from an optical cavity in suppressing the Auger recombination rate and highlights its technological importance.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Analytical
Araghni Bhattacharya, Satyajit Mahata, Ashutosh Bandyopadhyay, Biman B. Mandal, Vadivelu Manivannan
Summary: The molecule 2,4,5-tris(2-pyridyl)imidazole (L) has been evaluated as a probe for dual sensing of Hg2+ and Cu2+ ions. It shows a sensitive and selective response in the presence of both ions and can detect them in specific pH ranges. The probe's detection limit for Cu2+ is below the allowable limit prescribed by the United States Environmental Protection Agency. Experimental observations are supported by calculations and cell imaging studies.
Article
Nanoscience & Nanotechnology
Ankit Udai, Swaroop Ganguly, Pallab Bhattacharya, Dipankar Saha
Summary: This study investigates the ultrafast carrier dynamics of bound states in In0.14Ga0.86N/GaN quantum wells using femtosecond transient absorption spectroscopy. It reveals that both the ground and excited states contribute to the overall dynamics, which can be decoupled in the absorption spectra and time-resolved dynamics.
Article
Nanoscience & Nanotechnology
Fu-Chen Hsiao, Arnab Hazari, Yia-Chung Chang, Pallab Bhattacharya, John M. Dallesasse
Summary: This study presents a comprehensive theoretical modeling of photocurrent spectra generated by an In0.91Ga0.09N/ In0.4Ga0.6N disk-in-wire photodiode. The calculated photocurrent spectra show good agreement with experimental data, and the physical mechanisms for the observed prominent peaks are identified and investigated.
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
(2022)
Article
Physics, Applied
Yuanpeng Wu, Ping Wang, Woncheol Lee, Anthony Aiello, Parag Deotare, Theodore Norris, Pallab Bhattacharya, Mackillo Kira, Emmanouil Kioupakis, Zetian Mi
Summary: Both 2D TMDs and III-V semiconductors are potential platforms for quantum technology, but each with its limitations. 2D TMDs have a large exciton binding energy and customizable quantum properties, but compatibility issues with existing industrial processes. On the other hand, III-nitrides have been widely used in light-emitting devices and power electronics but lack exploitation of excitonic quantum aspects. Recent advancements in 2D III-nitrides have shown promise in achieving room-temperature quantum technologies.
APPLIED PHYSICS LETTERS
(2023)
Article
Nanoscience & Nanotechnology
Anthony Aiello, Debabrata Das, Pallab Bhattacharya
Summary: In this study, InGaN/GaN quantum dot light-emitting diodes were demonstrated on silicon substrates with a planar buffer layer formed by coalescing GaN nanowires. The devices showed strong electroluminescence with a minimal blue shift and a polarization field. However, efficiency droop was observed beyond an injection of 40A/cm(2), possibly due to defect-assisted Auger recombination and carrier leakage from the active region.
ACS APPLIED NANO MATERIALS
(2021)
Proceedings Paper
Engineering, Electrical & Electronic
Kunook Chung, Ayush Pandey, Tuba Sarwar, Anthony Aiello, Zetian Mi, Pallab Bhattacharya, Pei-Cheng Ku
2020 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO)
(2020)
Proceedings Paper
Engineering, Electrical & Electronic
A. Pandey, A. Aiello, J. Gim, R. Hovden, E. Kioupakis, P. Bhattacharya, Z. Mi
2020 IEEE PHOTONICS CONFERENCE (IPC)
(2020)
Article
Engineering, Electrical & Electronic
Debabrata Das, Anthony Aiello, Wei Guo, Pallab Bhattacharya
IEEE TRANSACTIONS ON NANOTECHNOLOGY
(2020)