Browsing by Author "Krishnamanohara"

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    Investigation of charge transport in Vanadyl-phthalocyanine with molybdenum trioxide as a buffer layer: Impedance spectroscopic analysis
    (2015) Kiran, M.R.; Ulla, H.; Krishnamanohara; Satyanarayan, M.N.; Umesh, G.
    Charge transport in organic materials is one of the intrinsic properties, which governs the device performance. In this paper, we report the fabrication and electrical characterization of two diodes ITO/VOPc/MoO3/Al and ITO/VOPc/Al. We investigate the electrical conduction of Vanadyl phthalocyanine (VOPc) in both the devices and also the effect of MoO3 as a buffer layer. Improvement of current density through the device is estimated using current density - voltage characteristics and capacitance - voltage characteristics. Space charge limited current (SCLC) conduction with an exponential trap distribution is observed from Impedance measurements. The dominant hopping charge transport is discussed based on ac conductivity measurements and by adopting Correlated barrier hopping (CBH) model. 2015 Elsevier B.V. All rights reserved.
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    Investigation of charge transport in Vanadyl-phthalocyanine with molybdenum trioxide as a buffer layer: Impedance spectroscopic analysis
    (Elsevier Ltd, 2015) Raveendra Kiran, M.R.; Ulla, H.; Krishnamanohara; Satyanarayan, M.N.; Umesh, G.
    Charge transport in organic materials is one of the intrinsic properties, which governs the device performance. In this paper, we report the fabrication and electrical characterization of two diodes ITO/VOPc/MoO3/Al and ITO/VOPc/Al. We investigate the electrical conduction of Vanadyl phthalocyanine (VOPc) in both the devices and also the effect of MoO3 as a buffer layer. Improvement of current density through the device is estimated using current density - voltage characteristics and capacitance - voltage characteristics. Space charge limited current (SCLC) conduction with an exponential trap distribution is observed from Impedance measurements. The dominant hopping charge transport is discussed based on ac conductivity measurements and by adopting Correlated barrier hopping (CBH) model. © 2015 Elsevier B.V. All rights reserved.
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    Observation of resistance switching in Vanadyl-phthalocyanine thin films
    (Elsevier Ltd, 2020) Raveendra Kiran, M.R.; Ulla, H.; Krishnamanohara; Satyanarayan, M.N.; Umesh, G.
    Herein, we report the first observation of Negative differential resistance (NDR) associated with resistance switching in Vanadyl-phthalocyanine (VOPc) based devices with the configuration: ITO/F4TCNQ/VOPc/MoO3/Al. It was observed that the devices were initially at low resistance ON state (LS) and were switched to high resistance OFF state (HS) at sufficient applied bias. The NDR behaviour was observed during the initial sweep for each device (often referred to as the writing process). The ON/OFF state transition was attributed to the formation and neutralization of interface dipoles at the ITO/VOPc interface. Finally, the observed non-volatile RS switching behaviour was demonstrated employing impedance spectroscopic studies. This study opens up the potential applications of VOPc Resistance Switching devices in security and data protection applications. © 2020 Elsevier B.V.