Molecular modification of an ionic semiconductor–metal interface: ZnO/molecule/Au diodes

Salomon, Adi; Berkovich, Dvora; Cahen, David

doi:10.1063/1.1543638

Cited by 63 publications

(82 citation statements)

References 19 publications

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“…Furthermore, by using alkyl alcohols of different lengths as solvent rather than just methanol we tune the Si electron affinity and can measure the S parameter without changing the top metal electrode. 27 The HQ treatment that exhibits the largest surface dipole is that with MeOH. We show that the junction of this surface with Hg is strongly type-inverted and current across it is dominated by minority carrier transport.…”

Section: -3mentioning

confidence: 99%

“…We use here S mod instead of S, because the electron affinity of the Si was modified (i.e., X becomes X eff ), rather than the metal work function, 27,36 though from electrostatic considerations changing either parameter should have the same impact on SBH. The present Si-molecules-Hg system appears unique in that it conforms to the Schottky-Mott model almost perfectly, with S mod =0.89, whereas other Si systems, and not only those prepared and measured under ambient conditions, fail to do so.…”

Section: -4mentioning

confidence: 99%

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Ambient organic molecular passivation of Si yields near-ideal, Schottky-Mott limited, junctions

et al. 2012

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We report near-perfect transfer of the electrical properties of oxide-free Si surface, modified by a molecular monolayer, to the interface of a junction made with that modified Si surface. Such behavior is highly unusual for a covalent, narrow bandgap semiconductor, such as Si. Short, ambient atmosphere, room temperature treatment of oxide-free Si(100) in hydroquinone (HQ)/alkyl alcohol solutions, fully passivates the Si surface, while allowing controlled change of the resulting surface potential. The junctions formed, upon contacting such surfaces with Hg, a metal that does not chemically interact with Si, follow the Schottky-Mott model for metal-semiconductor junctions closer than ever for Si-based junctions. Two examples of such ideal behavior are demonstrated: a) Tuning the molecular surface dipole over 400 mV, with only negligible band bending, by changing the alkyl chain length. Because of the excellent passivation this yields junctions with Hg with barrier heights that follow the change in the Si effective electron affinity nearly ideally. b) HQ/ methanol passivation of Si is accompanied by a large surface dipole, which suffices, as interface dipole, to drive the Si into strong inversion as shown experimentally via its photovoltaic effect. With only ∼0.3 nm molecular interlayer between the metal and the Si, our results proves that it is passivation and prevention of metal-semiconductor interactions that allow ideal metal-semiconductor junction behavior, rather than an insulating transport barrier.

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Section: -3mentioning

confidence: 99%

Section: -4mentioning

confidence: 99%

Ambient organic molecular passivation of Si yields near-ideal, Schottky-Mott limited, junctions

et al. 2012

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“…3 A stable and good quality rectifying metal contact on the n-ZnO surface is crucial for many optoelectronic applications and remains a challenge despite numerous recent investigations. [3][4][5][6] The realization of high quality Schottky contacts on ZnO nanostructures seems to be difficult because of the interface states, the surface morphology, hydroxide surface contamination, and the subsurface defects, which all play important roles in the electrical properties of these contacts. 7 In recent years, a number of process methodologies have been developed for the fabrication of reproducible high quality Schottky contacts on ZnO nanostructures, but controversies remain with regard to the Schottky barrier height and the factor of the ZnO Schottky contacts.…”

Section: Introductionmentioning

confidence: 99%

Systematic study of interface trap and barrier inhomogeneities using I-V-T characteristics of Au/ZnO nanorods Schottky diode

Hussain

Soomro

Bano

et al. 2013

Journal of Applied Physics

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This paper presents in-depth analysis of I-V-T characteristics of Au/ZnO nanorods Schottky diodes. The temperature dependence I-V parameters such as the ideality factor and the barrier heights have been explained on the basis of inhomogeneity. Detailed and systematic analysis was performed to extract information about the interface trap states. The ideality factor decreases, while the barrier height increases with increase of temperature. These observations have been ascribed to barrier inhomogeneities at the Au/ZnO nanorods interface. The inhomogeneities can be described by the Gaussian distribution of barrier heights. The effect of tunneling, Fermi level pinning, and image force lowering has contribution in the barrier height lowering. The recombination-tunneling mechanism is used to explain the conduction process in Au/ZnO nanorods Schottky diodes. The ionization of interface states has been considered for explaining the inhomogeneities.

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“…4 A stable and good quality rectifying metal contact on the n-ZnO surface is crucial for many optoelectronic applications and remains a challenge despite numerous recent investigations. [4][5][6][7] The realization of high quality Schottky contacts on ZnO nanostructures seems to be difficult because of the interface states, the surface morphology, hydroxide surface contamination, and the subsurface defects, which all play important roles in the electrical properties of these contacts. 4 In recent years, a number of process methodologies have been developed for the fabrication of reproducible high quality Schottky contacts on ZnO nanostructures, but controversies remain with regard to the Schottky barrier height and the ideality factor of the ZnO Schottky contacts.…”

Section: Introductionmentioning

confidence: 99%

Interface trap characterization and electrical properties of Au-ZnO nanorod Schottky diodes by conductance and capacitance methods

Hussain

Soomro

Bano

et al. 2012

Journal of Applied Physics

108

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Schottky diodes with Au/ZnO nanorod (NR)/n-SiC configurations have been fabricated and their interface traps and electrical properties have been investigated by current-voltage (I-V), capacitance-voltage (C-V), capacitance-frequency (C-f), and conductance-frequency (G p /x-x) measurements. Detailed and systematic analysis of the frequency-dependent capacitance and conductance measurements was performed to extract the information about the interface trap states. The discrepancy between the high barrier height values obtained from the I-V and the C-V measurements was also analyzed. The higher capacitance at low frequencies was attributed to excess capacitance as a result of interface states in equilibrium in the ZnO that can follow the alternating current signal. The energy of the interface states (E ss ) with respect to the valence band at the ZnO NR surface was also calculated. The densities of interface states obtained from the conductance and capacitance methods agreed well with each other and this confirm that the observed capacitance and conductance are caused by the same physical processes, i.e., recombination-generation in the interface states. V C 2012 American Institute of Physics.

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Molecular modification of an ionic semiconductor–metal interface: ZnO/molecule/Au diodes

Abstract: Influence of thin metal nanolayers on the photodetective properties of ZnO thin films

Cited by 63 publications

References 19 publications

Ambient organic molecular passivation of Si yields near-ideal, Schottky-Mott limited, junctions

Ambient organic molecular passivation of Si yields near-ideal, Schottky-Mott limited, junctions

Systematic study of interface trap and barrier inhomogeneities using I-V-T characteristics of Au/ZnO nanorods Schottky diode

Interface trap characterization and electrical properties of Au-ZnO nanorod Schottky diodes by conductance and capacitance methods

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