title: Resistive switching memory characteristics of Ge/GeOx nanowires and evidence of oxygen ion migration.
abstract: The resistive switching memory of Ge nanowires (NWs) in an IrOx/Al2O3/Ge NWs/SiO2/p-Si structure is investigated. Ge NWs with an average diameter of approximately 100 nm are grown by the vapor-liquid-solid technique. The core-shell structure of the Ge/GeOx NWs is confirmed by both scanning electron microscopy and high-resolution transmission electron microscopy. Defects in the Ge/GeOx NWs are observed by X-ray photoelectron spectroscopy. Broad photoluminescence spectra from 10 to 300 K are observed because of defects in the Ge/GeOx NWs, which are also useful for nanoscale resistive switching memory. The resistive switching mechanism in an IrOx/GeOx/W structure involves migration of oxygen ions under external bias, which is also confirmed by real-time observation of the surface of the device. The porous IrOx top electrode readily allows the evolved O2 gas to escape from the device. The annealed device has a low operating voltage (<4 V), low RESET current (approximately 22 μA), large resistance ratio (>103), long pulse read endurance of >105 cycles, and good data retention of >104 s. Its performance is better than that of the as-deposited device because the GeOx film in the annealed device contains more oxygen vacancies. Under SET operation, Ge/GeOx nanofilaments (or NWs) form in the GeOx film. The diameter of the conducting nanofilament is approximately 40 nm, which is calculated using a new method.
authors: Department of Electronic Engineering, Chang Gung University, 259 Wen-Hwa 1st Rd,, Kwei-Shan, Tao-Yuan 333, Taiwan. sidhu@mail.cgu.edu.tw.
authors: Amit
authors: A
authors: Prakash
authors: Siddheswar
authors: S
authors: Maikap
authors: Sheikh Ziaur
authors: SZ
authors: Rahaman
authors: Sandip
authors: S
authors: Majumdar
authors: Santanu
authors: S
authors: Manna
authors: Samit K
authors: SK
authors: Ray
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