Low-dimensional materials for nanocomputing devices.
Abstract
As the nature and complexity of computational tasks in Navy-related applications morph and increase, novel nanomaterials attract int,erest as a medium for new devices and circuits/architectures to meet Navy?s targets. One of the outstanding challenges is the data s,ecurity/encryption in need of a true random number generator (TRNG), combining (i) speed, (ii) power efficiency, and (iii) bit-strea,m quality. This is where 2D materials can offer a clear advantage ? a TRNG based on current fluctuations (random telegraph noise, RT,N) in a Ni||(few-layer)h-BN||Au system is outstandingly random and stable in data encryption. Stability has also been highlighted in, conjunction with multistate randomness in MoS2-based heterostructures. Due to the open area nature of low-dimensional materials, a,n extrinsic charge-trap fluctuator can be in proximity to the 1D- or 2D-channel in a FET-nanodevice, achieving higher scattering sen,sitivity in comparison to bulk devices: The spatial/structural separation of the channel and the fluctuator does offer means for dev,ice tunability. A physisorbed charge-trap can be a redox-active molecule, viable candidates being porphyrin-based, Keggin-type (e.g.,, phosphomolybdic acid, PMA), etc, or smaller electrically bistable molecules such as the diphenyl bithiophene derivatives. The emer,ging examples of TRNG from low-dimensional materials compel us to elucidate and quantify the key operating mechanisms, such as non-r,adiative carrier capture, using high-fidelity first-principles approaches, to select and optimize the best candidates.While the main, focus is on charge-trap fluctuations, a parallel line of work is on 2D memristors: to elucidate the resistance-switching mechanisms, in these neuromorphic devices operating on the principles similar to those of the human brain. A microscopic connection between the, change of ion oxidation state and variation of the material resistivity has not been yet firmly established; scattering and doping,mechanisms have been considered. We propose a theoretical exploration of resistance switching mechanisms in selected classes of memr,istive materials and devices, including (i) 2D single-layer transition metal dichalcogenides, TMD; (ii) MXenes, e.g., Ti(n+1)XnTX, w,ith X = C,N, and Tx ? terminating functional group, and (iii) other few-layer 2D and bulk materials such as transition metal oxides., We aim, helped by the first-principle simulations, to discern microscopic commonality and thus build general models applicable for,different dimensionalities and classes of materials. We plan to identify, from first principles underlying the switching mechanisms.,The line of research on emergent materials for electronics will focus on a 2D-diamond, known as diamane (high thermal conductivity,,mechanical stiffness, carrier mobility), also promising for quantum computing, as we predict that a NV defect in a diamane host can,be an emitter of a single-photon ? ?photonic qubit?. In order for devices to benefit from diamane, one needs the desired type of con,ductivity via doping. Calculations suggest that p- and n-type diamane may be achievable by means of modulation or transfer doping. P,olar interfaces create large band offsets that can be utilized in modulation doping. The task is yet notably difficult but is ideall,y suited to assess using first-principles calculations.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Oct 07, 2022
- Source ID
- N000142212753
Entities
People
- Boris I Yakobson
Organizations
- Office of Naval Research
- Rice University
- United States Navy