Controlled modification of resonant tunneling in metal-insulator-insulator-metal structures

Mitrovic, IZ ORCID: 0000-0003-4816-8905, Weerakkody, DADC, Sedghi, N ORCID: 0000-0002-2004-6159, Ralph, Jason F ORCID: 0000-0002-4946-9948, Hall, S ORCID: 0000-0001-8387-1036, Dhanak, VR, Luo, Z and Beeby, S
(2018) Controlled modification of resonant tunneling in metal-insulator-insulator-metal structures. Applied Physics Letters, 112 (1).

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We present comprehensive experimental and theoretical work on tunnel-barrier rectifiers comprising bilayer (Nb2O5/Al2O3) insulator configurations with similar (Nb/Nb) and dissimilar (Nb/Ag) metal electrodes. The electron affinity, valence band offset, and metal work function were ascertained by X-ray photoelectron spectroscopy, variable angle spectroscopic ellipsometry, and electrical measurements on fabricated reference structures. The experimental band line-up parameters were fed into a theoretical model to predict available bound states in the Nb2O5/Al2O3 quantum well and generate tunneling probability and transmittance curves under applied bias. The onset of strong resonance in the sub-V regime was found to be controlled by a work function difference of Nb/Ag electrodes in agreement with the experimental band alignment and theoretical model. A superior low-bias asymmetry of 35 at 0.1 V and a responsivity of 5 A/W at 0.25 V were observed for the Nb/4 nm Nb2O5/1 nm Al2O3/Ag structure, sufficient to achieve a rectification of over 90% of the input alternate current terahertz signal in a rectenna device.

Item Type: Article
Depositing User: Symplectic Admin
Date Deposited: 02 Jan 2018 16:45
Last Modified: 19 Jan 2023 06:46
DOI: 10.1063/1.4999258
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