Electrical, thermal, and strain-dependent characterization of transition metal dichalcogenide-based devices
Abstract/Contents
- Abstract
- For over half a century, the performance of integrated electronics has significantly improved by reducing the dimensions of silicon-based logic and memory devices. However, as silicon scaling approaches its limits, researchers are investigating new materials for transistors, memory, and their three-dimensional (3D) integration on the same chip to enable higher density and better energy efficiency. Two-dimensional (2D) materials, in particular semiconducting transition metal dichalcogenides (TMDs), have demonstrated excellent electrical properties even in atomically thin films. In addition, these materials are promising for 3D architectures due to their ability to be integrated with various device structures at low temperatures. In this thesis, I will describe various experimental techniques to study TMD-based memory and transistors. First, I study switching behavior in resistive memory devices based on molybdenum ditelluride (MoTe2). I use scanning thermal microscopy (SThM) combined with electro-thermal simulations to investigate heating in the devices during operation. The SThM measurements, together with electrical measurements and transmission electron microscopy imaging, help uncover the switching mechanism in these devices and provide the first thermal insights into the operation of such TMD-based resistive memory. Next, I demonstrate a simple pulsed voltage measurement technique to reduce hysteresis due to charge trapping in current-voltage measurements of MoS2 transistors. I compare devices fabricated from exfoliated and synthetic MoS2, with SiO2 and HfO2 gate insulators, using both DC and pulsed voltage measurements. The hysteresis is reduced by ~80% in all devices at modest voltage pulses of ~1 ms applied to the gate of the transistors, enabling accurate extractions of threshold voltage and field-effect mobility. Finally, I explore the effects of strain on the optical and electrical properties of monolayer TMDs. First, photoluminescence measurements of MoTe2 with tensile strain reveal narrowing of the optical band gap and indicate reduced exciton-phonon intervalley scattering. Next, I apply tensile strain to MoS2 transistors and demonstrate an improvement in current and mobility by up to a factor of two. These results suggest that strain might play an important role for integrated 2D electronics, as it has for silicon. This work improves our understanding of TMD-based devices, which are promising for both logic and memory in next-generation electronics
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2020; ©2020 |
| Publication date | 2020; 2020 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Datye, Isha Madhurima |
|---|---|
| Degree supervisor | Pop, Eric |
| Thesis advisor | Pop, Eric |
| Thesis advisor | Reed, Evan J |
| Thesis advisor | Saraswat, Krishna |
| Degree committee member | Reed, Evan J |
| Degree committee member | Saraswat, Krishna |
| Associated with | Stanford University, Department of Electrical Engineering |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Isha Madhurima Datye |
|---|---|
| Note | Submitted to the Department of Electrical Engineering |
| Thesis | Thesis Ph.D. Stanford University 2020 |
| Location | https://purl.stanford.edu/qb884wb9709 |
Access conditions
- Copyright
- © 2020 by Isha Madhurima Datye
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
Also listed in
Loading usage metrics...