Bhattacharjee, Shubhadeep and Vatsyayan, Ritwik and Ganapathi, Kolla Lakshmi and Ravindra, Pramod and Mohan, Sangeneni and Bhat, Navakanta (2019) Hole Injection and Rectifying Heterojunction Photodiodes through Vacancy Engineering in MoS2. In: ADVANCED ELECTRONIC MATERIALS, 5 (6).
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Abstract
The lack of techniques for counter doping in two dimensional (2D) semiconductors has hindered the development of p/n junctions, which are the basic building blocks of electronic devices. In this work, low-energy argon ions are used to create sulfur vacancies and are subsequently ``filled'' with oxygen to create p-doped MoS2-xOx. The incorporation of oxygen into the MoS2 lattice and hence band-structure modification reveal the nature of the p-type doping. These changes are validated by X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, Raman spectroscopy, and photoluminescence measurements combined with density functional theory calculations. Electrical measurements reveal a complete flip in carrier polarity from n-type to p-type, which is further examined using temperature-dependent transport measurements. The enhancement of p-field-effect transistor characteristics is facilitated by employing top-gated transistors and area-selective vacancy engineering only in the contact regions. Finally, on the same flake, an in-plane MoS2 (n)/MoS2-xOx (p) type-I (straddling) heterojunction with rectifying behavior and excellent broadband photoresponse is demonstrated and explained using band diagrams. The spatial/metallurgical abruptness (<100 nm) of the heterojunctions is ascertained using Raman mapping. This process of vacancy engineering, which enables air-stable, area-selective, controlled, CMOS-compatible doping of 2D semiconductors is envisioned to open new vistas in the development of high-performance electronic and optoelectronic devices.
| Item Type: | Journal Article |
|---|---|
| Publication: | ADVANCED ELECTRONIC MATERIALS |
| Publisher: | WILEY |
| Additional Information: | copyright for this article belongs to WILEY |
| Keywords: | heterojunctions; p-doping; photodiodes; Raman mapping; vacancy engineering |
| Department/Centre: | Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering |
| Date Deposited: | 31 Jul 2019 06:55 |
| Last Modified: | 31 Jul 2019 06:55 |
| URI: | http://eprints.iisc.ac.in/id/eprint/63137 |
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