Browsing by Author "Hu, Ying"

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An Electronic Synapse Device Based on Solid Electrolyte Resistive Random Access Memory
(2015-08-01)
Zhang, Wei
;
Hu, Ying
;
Chang, Ting-Chang
;
Chang, Kuan-Chang
;
Tsai, Tsung-Ming
The multilevel capability of solid electrolyte resistive random access memory (RRAM) with a Pt/GeSO/TiN structure was explored for potential use as a synapse device. By varying the cutoff voltage during the dc I-V cycles or the ac pulse programming voltage amplitudes, continuous multilevel conductance states were obtained. The reference Pt/GeO/TiN RRAM was fabricated to certify the multilevel capability and was due to the character of the GeS solid electrolyte. Finally, the property of gradual conductance states was exploited to demonstrate spike-timing-dependent plasticity learning, which suggests device\'s potential for use as an electronic synapse device for neuromorphic systems.
Electrical conduction mechanism of Zn:SiOx resistance random access memory with supercritical CO2 fluid process
(2013-08-19)
Chang, Kuan-Chang
;
Tsai, Tsung-Ming
;
Zhang, Rui
;
Chang, Ting-Chang
;
Chen, Kai-Huang
In this study, the electrical conduction mechanism of Zn:SiOx resistance random access memory (RRAM) treated with supercritical CO2 fluid (SCCO2) process was investigated by low temperature measurement. The current of low resistance state for current-voltage curves in SCCO2-treated and untreated Zn:SiOx RRAM were measured and compared under a low temperature range from 100K to 298 K. The electrical conduction mechanisms of hopping conduction and metal-like behaviors in SCCO2-treated and untreated Zn:SiOx RRAM were discussed, respectively. Finally, the electrical conduction mechanism was analyzed and verified by the chemical composition and bonding intensity of XPS analyses. (C) 2013 AIP Publishing LLC.
Franck-Condon simulation for unraveling vibronic origin in solvent enhanced absorption and fluorescence spectra of rubrene
(2017)
Hu, Ying
;
Wang, Chen-Wen
;
Zhu, Chaoyuan
;
Gu, Fenglong
;
Lin, Sheng-Hsien
Quantum chemistry calculations at the level of (TD)-DFT plus PCM solvent models are employed for analyzing potential energy surfaces and as a result two local minima with D-2, two local minima with C-2H, and one second-order transition state with D-2H group symmetry are found in both ground S-0 and excited-state S-1 potential energy surfaces. Simulated vibronic coupling distributions indicate that only second-order transition states with D-2H group symmetry are responsible for observed absorption and fluorescence spectra of rubrene and vibrational normal-motions related with atoms on the aromatic backbone are active for vibronic spectra. The Stokes shift 1120 cm(-1) (820 cm(-1)) and vibronic-band peak positions in both absorption and fluorescence spectra in non-polar benzene (polar cyclohexane) solvent are well reproduced within the conventional Franck-Condon simulation. By adding damped oscillator correction to Franck-Condon simulation, solvent enhanced vibronic-band intensities and shapes are well reproduced. Four (three) normal modes with vibration frequency around 1550 cm(-1) (1350 cm(-1)) related to ring wagging plus CC stretching and CH bend motions on the backbone are actually interpreted for solvent enhanced absorption (fluorescence) spectra of rubrene in benzene and cyclohexane solutions.
Franck-Condon simulation for unraveling vibronic origin in solvent enhanced absorption and fluorescence spectra of rubrene
(2017-01-01)
Hu, Ying
;
Wang, Chen-Wen
;
Zhu, Chaoyuan
;
Gu, Fenglong
;
Lin, Sheng-Hsien
Quantum chemistry calculations at the level of (TD)-DFT plus PCM solvent models are employed for analyzing potential energy surfaces and as a result two local minima with D-2, two local minima with C-2H, and one second-order transition state with D-2H group symmetry are found in both ground S-0 and excited-state S-1 potential energy surfaces. Simulated vibronic coupling distributions indicate that only second-order transition states with D-2H group symmetry are responsible for observed absorption and fluorescence spectra of rubrene and vibrational normal-motions related with atoms on the aromatic backbone are active for vibronic spectra. The Stokes shift 1120 cm(-1) (820 cm(-1)) and vibronic-band peak positions in both absorption and fluorescence spectra in non-polar benzene (polar cyclohexane) solvent are well reproduced within the conventional Franck-Condon simulation. By adding damped oscillator correction to Franck-Condon simulation, solvent enhanced vibronic-band intensities and shapes are well reproduced. Four (three) normal modes with vibration frequency around 1550 cm(-1) (1350 cm(-1)) related to ring wagging plus CC stretching and CH bend motions on the backbone are actually interpreted for solvent enhanced absorption (fluorescence) spectra of rubrene in benzene and cyclohexane solutions.
Low Temperature Improvement Method on Zn:SiOx Resistive Random Access Memory Devices
(2013-04-01)
Chang, Kuan-Chang
;
Tsai, Tsung-Ming
;
Chang, Ting-Chang
;
Wu, Hsing-Hua
;
Chen, Kai-Huang
To improve the resistive switching properties of the resistive random access memory (RRAM), the supercritical carbon dioxide (SCCO2) fluid is used as a low temperature treatment. In this letter, the Zn:SiOx thin films are treated by SCCO2 fluid mixed with pure water. After SCCO2 fluid treatment, the resistive switching qualities of the Zn:SiOx thin films are carried out by XPS, fourier transform infrared spectroscopy, and IV measurement. We believe that the SCCO2-treated Zn:SiOx thin film is a promising material for RRAM applications due to its compatibility with portable flat panel display.
Mechanism of Triple Ions Effect in GeSO Resistance Random Access Memory
(2015-06-01)
Zhang, Wei
;
Hu, Ying
;
Chang, Ting-Chang
;
Tsai, Tsung-Ming
;
Chang, Kuan-Chang
In this letter, a triple-ion redox reaction has been proposed and investigated in GeSO-based resistance random access memory. Continuous multiresistance states can be obtained by applying a series of increasing cutoff voltages in both set and reset processes. Using data retention tests, these multistates in the set and reset processes were confirmed to be stable. The conduction mechanism gradually changed during reset process from space charge limited current to Schottky emission. A triple-ion reaction model has been proposed to reveal the chemical reaction properties in the resistive switching process.