Title
Gated 2D material quantum dot and nanowire quantum dot for quantum information technology
The field of quantum devices is witnessing a revolutionary change over the years with the remarkable progress in the area of quantum bits (or qubits) . A qubit is the quantum analogue of the classical computing bit and lays the foundation for quantum computers. In principle, quantum computers aren’t just restricted to conventional binary bits i.e., 0s or 1s, but can encode information in the form of qubits, which are basically quantum systems with two distinguishable configurations equivalent to the bit values 0 and 1. But since, qubits follow the principles of a quantum system, they also support superposition and entanglement . Hence, quantum computing can support enormous combination of states simultaneously, with a tremendous potential to outperform even the best of supercomputers. But the key challenges in developing efficient quantum architectures are to have a system with a satisfactorily large number of operations, within the characteristic coherence time limits of the qubits. Undoubtedly, the targeted quantum applications rely strongly on the material implementation and quantum hardware, thus continuous research efforts are being directed towards the large-scale integration of plausible materials in this regime. Given the high efficacy of semiconductor devices towards the realization of classical computation, it was natural to consider the same systems for quantum information processors. So far, qubits with charge degree of freedom of electron in double quantum dot(DQD), namely charge qubit is used for realizing the strength of quantum system but as the charge qubit is very susceptible to environment fluctuations, coherence time related to it is very limited. Therefore, in next, spin degree of freedom of an electron or hole in a quantum dot (QD) is used to realise spin qubit. It is a prominent competitor as a quantum mechanical object for quantum bit realization . The spin qubit has a large dephasing time and less susceptible to external noise, making it most suited for practical applications. Along with the spin degree of freedom, electrons and hole possess another degree of freedom called ‘valley’ degree of freedom which is related to the crystal structure of the materials. This extra degree of freedom is equally useful to create quantum bits and a relatively new field is emerging named as ‘valleytronics’ . Study of valley electronics in 2D materials is of particular interest because they provide inherent one-dimensional confinement. The confinement of the charge carriers can be made inside an electrostatically depleted 2D material. The formation of the nanostructures using 2D materials is challenging, however, there is a significant progress in the development electrostatically depleted (or gated) QDs . The gated QDs provides better control on the charge confinement length and the improved spin orbit coupling in some 2D materials (such as WSe2) are the key motivation of this proposed research. The broad objective of this proposed research is to study the spin valley electronic properties of gate defined 2D materials quantum dot QD. The specific objectives of this proposed work can be summarized as Synthesis of single/few layers of 2D materials (such as WSe2) on high-k dielectric Hfo2 or on Al2O3 or on SiO2 using molecular beam epitaxy MBE and Atomic Layer Deposition ALD, mechanical exfoliation and novel chemical synthesis methods patented by the applicants. Quantum electronic transport of grown/transferred 2D materials. Fabrication and quantum transport measurement of gated 2D quantum dot, nanowire quantum dot for the realization of Quantum devices for Quantum information Technologies.
The spin degree of freedom of an electron or hole in a quantum dot (QD is a prominent competitor as a quantum mechanical object for quantum bit realization. The spin qubit has a large dephasing time and is less susceptible to external noise, making it most suited for practical applications. Along with the spin degree of freedom, electrons and hole possess another degree of freedom called the ‘valley’ degree of freedom which is related to the crystal structure of the materials. This extra degree of freedom is equally useful to create quantum bits and a relatively new field is emerging named ‘valleytronics’ The study of valley electronics in 2D materials is of particular interest because they provide inherent one-dimensional confinement. The confinement of the charge carriers can be made inside an electrostatically depleted 2D material. The formation of the nanostructures using 2D materials is challenging, however, there is significant progress in the development of electrostatically depleted (or gated) QDs . The gated QDs provide better control on the charge confinement length and the improved spin-orbit coupling in some 2D materials (such as WSe2) are the key motivation of this proposed research. The broad objective of this proposed research is to study the spin valley electronic properties of gate-defined 2D materials quantum dot QD for the development of quantum devices for Quantum information Technologies.
The project aims at developing an innovative technological platform for quantum information technology. The main objective is to design, realize, and characterize a nanodevice based on gate-defined quantum dots (QD) within a single layer of transition metal di-selenides. The Dirac fermion Hamiltonian about the low-energy states in such materials offers nontrivial properties. The project will specifically engineer and encode data in the valley degree of freedom offered by two-dimensional (2D) TMD. The valley coherence and its accessibility by electrical and optical means will open unmatched possibilities for quantum information processing, enabling room temperature operation to a level unattainable with current qubit technologies. The project will leverage quantum control of electron spin entanglement via intervalley terms thus addressing single- and two-qubit gates operations and complemented by optical control of a single quantum dot.
Objectives :
Objective-1: Synthesis of single/few layers of 2D materials (such as WSe2) using molecular beam epitaxy(MBE)
Objective-2: Quantum transport properties of grown 2D materials using hall bar structure
Objective-3: Fabrication of Semiconductor based Quantum Dot (QD)
(a)Gate defined Quantum dot
(b)Nanowire based Quantum dot (QD)
Objective-4: Electronic Transport Measurement of fabricated quantum devices for quantum information processing
Nanowire based transistor: In recent years, nanowire junctionless transistors (NW-JNTs) came into lime light due to feasibility of extreme miniaturization with less transverse effect of miniaturization. Owing this view,we studied nanowire JNT based trigated MOSFET,which was highly doped and we find find the coulmb diamond corresponding to dopant quantum dot(QD) present in the chanel.
1 PYL726 Semiconductor Device Technology
2 CRL722 RF and Microwave Solid State Device
3 ELL745 Quantum Electronics
4 PYL739 Computational Technique for Solid State Material
Journal:
Uddin Wasi, Biswajit Khan, Sheetal Dewan, and Samaresh Das. "Silicon-based qubit technology: progress and future prospects." Bulletin of Materials Science 45, no. 1 (2022): 1-20.
Conference :
Presentation in IWPSD-2021 on the topic entitled with “One dimensional Quantum Transport in ultra short junctionless Tri-GATE MOSFET”
Prime Minister Research Fellow
Center for Applied Research in Electronics (CARE)
Indian Institute of Technology ,Delhi
CARE, Block-III, First Floor IIT Delhi, India (110016)
Semester-2 (2021-2022)
Place of Work Center for Applied Research in Electronics (CARE),IIT Delhi,India.
Position Institute Teaching Assistantship
Nature of Work Instrumental TA
Instrument’s Name Laser Writter for Microfabrication
Workload 8-9 hours per week
Semester-1(2022-2023)
TA-1:
Place of Work Nano Research facility (NRF), IIT Delhi ,India
Position Institute Teaching Assistantship
Nature of Work Instrumental TA
Instrument’s Name Electron Beam Lithography(EBL)
Workload 6-7 hours per week
TA-2 :
Place of Work Center for Applied Research in Electronics (CARE),IIT Delhi,India.
Position Institute Teaching Assistantship
Class CRP-723 (Fabrication Techniques for RF and Microwaves
Course Coordinators Prof. Samaresh Das
Nature of Work Took two Tutorial Classes, Demonstration, Course examination & copy check
Workload 4 hours per week
TA-3: Non institutional TA ship
Place of Work GB Pant DSEU Okhla 1 Campus,Okhla Phase-,New Delhi
Position Teaching Assistantship at near Engineering College
Class Analog and Interfacing Circuits
Course Coordinators Sanjay Kumar
Nature of Work Completed Lab manual and assigned for taking Practical Class
Workload 1 hour per week
Planned Work: Planning to take TA ship training in Central Research facility (CRF) for Cryo –Prober from December,2022
Ph.D. (Ongoing), Research Domain:Semiconductor based Quantum information Technology
M.Tech., Radio Physics and Electronics, (Institute of Radio Physics and Electronics) Specialization: Nanoelectronics & Photonics
Post-B.Sc. B.Tech., Radio Physics and Electronics, (Institute of Radio Physics and Electronics)
B.Sc. Honours in Physics