Spin Transport and Magneto-Resistance in Organic Semiconductors

2009 ◽  
Vol 1154 ◽  
Author(s):  
Mohammad Yunus ◽  
P. P. Ruden ◽  
Darryl L. Smith
Keyword(s):  
Organic Semiconductors ◽  
Diffusion Approximation ◽  
Carrier Transport ◽  
Spin Transport ◽  
Spin Injection ◽  
Carrier Injection ◽  
Drift Diffusion ◽  
Spin Currents ◽  
Magneto Resistance

AbstractCalculated results for spin injection, transport, and magneto-resistance (MR) in organic semiconductors sandwiched between two ferromagnetic contacts are presented. The carrier transport is modeled by spin dependent device equations in drift-diffusion approximation. In agreement with earlier results, spin injection from ferromagnetic contacts into organic semiconductors can be greatly enhanced if (spin-selective) tunneling is the limiting process for carrier injection. Modeling the tunnel processes with linear contact resistances yields spin currents and MR that tend to increase with increasing bias. We also explore the possibility of bias dependent contact resistances and show that this effect may limit MR to low bias.

Ambipolar electrical spin injection and spin transport in organic semiconductors

2008 ◽  
Vol 103 (10) ◽  
pp. 103714 ◽  
Author(s):  
M. Yunus ◽  
P. P. Ruden ◽  
D. L. Smith
Keyword(s):  
Organic Semiconductors ◽  
Spin Transport ◽  
Spin Injection ◽  
Electrical Spin

Preparation of Lateral Organic Spin-valve Devices with La0.7Sr0.3MnO3

2007 ◽  
Vol 1033 ◽  
Author(s):  
Tomonori Ikegami ◽  
Iwao Kawayama ◽  
Masayoshi Tonouchi ◽  
Yoshiro Yamashita ◽  
Hirokazu Tada
Keyword(s):  
Organic Semiconductors ◽  
Spin Injection ◽  
Spin Valve ◽  
Epitaxial Films ◽  
Organic Films ◽  
Low Molecular Weight ◽  
Applied Bias ◽  
Metal Electrodes ◽  
Half Metal ◽  
Magneto Resistance

AbstractSpin injection and transport characteristics of low-molecular-weight organic semiconductors such as pentacene and bis(l,2,5-thiadiazolo)-p-quinobis(l,3-dithiole) (BTQBT) have been studied utilizing lateral type spin-valve devices with half metal electrodes, LaA0.67Sr0.33MnO3 (LSMO). The LSMO electrodes with a spacing of 200 nm were prepared by electron-beam lithography and dry etching of the epitaxial films grown on MgO substrates. The devices showed clear spin-valve behaviors with a magneto-resistance (MR) ratio up to 29 % at 9.1K. It was found that the MR ratio depended on the crystallinity of organic films as well as on temperature and applied bias voltages

Modeling of Spin Injection and Spin Transport Properties in Organic and Inorganic Semiconductors

2005 ◽  
Vol 871 ◽  
Author(s):  
P. P. Ruden ◽  
J. D. Albrecht ◽  
D. L. Smith
Keyword(s):  
Charge Carrier ◽  
Thermal Equilibrium ◽  
Spin Transport ◽  
Spin Injection ◽  
Molecular Crystals ◽  
Carrier Injection ◽  
Inorganic Semiconductors ◽  
Organic Molecular Crystals ◽  
Spin Polarized ◽  
Charge Carrier Injection

AbstractSpin polarized charge carrier injection and transport in non-magnetic semiconductors is a key enabling mechanism for spin based electronic data processing. We present theoretical models to describe spin injection and spin transport in structures consisting of a ferromagnetic metal injector, a thin semiconductor layer, and a ferromagnetic metal collector. The semiconductors considered are conjugated polymers (e.g. PPV), small-molecule organic molecular crystals (e.g. pentacene), and inorganic semiconductors (e.g. silicon). In thermal equilibrium the charge carriers in these semiconductors are not spin polarized. Efficient spin injection requires that the semiconductor be driven far out of local thermal equilibrium. Since carrier mobilities (and other relevant parameters) in polymers, organic molecular crystals, and inorganic semiconductors differ by many orders of magnitude, their charge carrier injection characteristics differ significantly.

Revealing the mechanism of carrier transport in host-guest systems of organic materials with a modified Poisson and drift-diffusion solver

2020 ◽  
Vol 4 (12) ◽  
Author(s):  
Jun-Yu Huang ◽  
Jiun-Haw Lee ◽  
Yuh-Renn Wu ◽  
Tse-Ying Chen ◽  
Yu-Cheng Chiu ◽  
...  
Keyword(s):  
Carrier Transport ◽  
Organic Materials ◽  
Drift Diffusion

Substantial and stable magnetoresistance and spin conductance in phosphorene-based spintronic devices with Co electrodes

2021 ◽  
Author(s):  
Zhao Chen ◽  
Guojun Li ◽  
Haidi Wang ◽  
Qiong Tang ◽  
ZhongJun Li
Keyword(s):  
Spin Transport ◽  
Spin Injection ◽  
Injection Efficiency ◽  
Tunnel Magnetoresistance ◽  
Spintronic Devices ◽  
Magnetoresistance Ratio ◽  
Large Tunnel ◽  
Spin Conductance

Phosphorene-based device with fcc Co(111) electrodes shows excellent spin transport characteristics: large tunnel magnetoresistance ratio and stable spin injection efficiency.

scholarly journals Análisis de la característica corriente-voltaje de diodos orgánicos emisores de luz (OLEDs) basados en polímeros depositados por spin coating.

2010 ◽  
Vol 15 (1) ◽  
pp. 68 ◽  
Author(s):  
Henry Alberto Méndez-Pinzón ◽  
Diana Rocío Pardo-Pardo ◽  
Juan Pablo Cuéllar-Alvarado ◽  
Juan Carlos Salcedo-Reyes ◽  
Ricardo Vera ◽  
...  
Keyword(s):  
Organic Semiconductors ◽  
Spin Coating ◽  
Electrical Response ◽  
Thermionic Emission ◽  
Hole Transport ◽  
Organic Layer ◽  
Electric Response ◽  
Carrier Injection ◽  
Parasitic Currents ◽  
Spin Coater

<p>Polymer-based organic light-emitting diodes (OLEDs) with the structure ITO / PEDOT:PSS / MDMO-PPV / Metal were prepared by spin coating. It is known that electroluminescence of these devices is strongly dependent on the material used as cathode and on the deposition parameters of the polymer electroluminescent layer MDMO-PPV. <strong>Objective.</strong> In this work the effect of i) the frequency of the spin coater (1000-8000 rpm), ii) the concentration of the MDMO-PPV: Toluene solution, and iii) the material used as cathode (Aluminium or Silver) on the electrical response of the devices, was evaluated through current-voltage (I-V) measurements. <strong>Materials and methods</strong>. PEDOT:PPS and MDMO-PPV organic layers were deposited by spin coating on ITO substrates, and the OLED structure was completed with cathodes of aluminium and silver. The electric response of the devices was evaluated based on the I-V characteristics. <strong>Results.</strong> Diodes prepared with thinner organic films allow higher currents at lower voltages; this can be achieved either by increasing the frequency of the spin coater or by using concentrations of MDMO-PPV: Toluene lower than 2% weight. A fit of the experimental data showed that the diodes have two contributions to the current. The first one is attributed to parasitic currents between anode and cathode, and the other one is a parallel current through the organic layer, in which the carrier injection mechanism is mediated by thermionic emission. <strong>Conclusions.</strong> The results fitting and the energy level alignment through the whole structure show that PPV-based OLEDs are unipolar devices, with current mainly attributed to hole transport.</p> <p><strong>Key words:</strong> organic semiconductors, OLEDs, electroluminescent polymers, MDMO-PPV, PEDOT:PSS, Spin coating, HOMO, LUMO, carrier injection, thermionic emission.</p><br />

1.55 μm High Speed Partly Gain-Coupled DFB Lasers with Periodically Etched Strained-Layer Quantum Wells

1997 ◽  
Vol 08 (03) ◽  
pp. 475-494 ◽  
Author(s):  
Toshihiko Makino
Keyword(s):  
Quantum Wells ◽  
High Speed ◽  
Carrier Transport ◽  
Stop Band ◽  
Longitudinal Distribution ◽  
Modulation Bandwidth ◽  
Carrier Injection ◽  
Strained Layer ◽  
High Modulation ◽  
Dfb Laser

The high speed performance of partly gain-coupled (GC) DFB lasers consisting of periodically etched strained-layer quantum wells (QW's) is reviewed with comparisons to the equivalent index-coupled (IC) DFB lasers with the same active layers. It is shown that the GC DFB laser has a –3 dB modulation bandwidth of 22 GHz at 10 mW with a stable single mode oscillation at the longer side of the Bragg Stop-band due to in-phase gain coupling. A theoretical analysis is also presented based on the local-normal-mode transfer-matrix laser model which takes into account both the longitudinal distribution of laser parameters and carrier transport effects. The mechanism for high modulation bandwidth of the GC DFB laser is attributed to a higher differential gain due to a reduced carrier transport time which is provided by an effecient carrier injection from the longitudinal etched interface of the QW's.

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