Discontinuous Molecular Films Can Control Metal/Semiconductor Junctions
Source abstract
Abstract
Molecular control over charge transport across a metal/semiconductor interface persists even if there is only a partial monolayer of polar molecules at the interface. This is because the long-range electrostatic effect of the dipole layer also affects the semiconductor regions under the film's pinholes. Thus, all types of polar molecules that show average order at the interface can be used.
Source: openalex_inverted_index · Quality: baseline
Research context
OpenAlex topics: Molecular Junctions and Nanostructures · Semiconductor materials and devices · Semiconductor materials and interfaces
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
References (47)
Show source-provided references
1. 10.1002/1521-4095(20020605)14:11<789::AID-ADMA789>3.0.CO;2-H10.1002/1521-4095(20020605)14:11<789::AID-ADMA789>3.0.CO;2-H ↗
2. 10.1002/cphc.20030094210.1002/cphc.200300942 ↗
3. 10.1021/ja020506c10.1021/ja020506c ↗
4. 10.1021/ar990047t10.1021/ar990047t ↗
5. 10.1038/3500453910.1038/35004539 ↗
6. 10.1002/(SICI)1521-4095(200003)12:6<447::AID-ADMA447>3.0.CO;2-810.1002/(SICI)1521-4095(200003)12:6<447::AID-ADMA447>3.0.CO;2-8 ↗
7. 10.1016/S0009-2614(98)00350-910.1016/S0009-2614(98)00350-9 ↗
8. 10.1039/b411490f10.1039/b411490f ↗
9. 10.1021/jp012708l10.1021/jp012708l ↗
10. 10.1063/1.154363810.1063/1.1543638 ↗
11. 10.1002/1521-4095(200104)13:7<508::AID-ADMA508>3.0.CO;2-810.1002/1521-4095(200104)13:7<508::AID-ADMA508>3.0.CO;2-8 ↗
12. 10.1002/1521-3773(20020301)41:5<827::AID-ANIE827>3.0.CO;2-N10.1002/1521-3773(20020301)41:5<827::AID-ANIE827>3.0.CO;2-N ↗
13. 10.1021/jp026779b10.1021/jp026779b ↗
14. 10.1103/PhysRevB.45.1350910.1103/PhysRevB.45.13509 ↗
15. 10.1007/BF0286920810.1007/BF02869208 ↗
16. Visoly‐Fisher I. · ChemPhysChem · 2004 · 10 · in press
17. 10.1021/ja990615010.1021/ja9906150 ↗
18. 10.1021/ja964434z10.1021/ja964434z ↗
19. 10.1021/ar980081s10.1021/ar980081s ↗
20. 10.1116/1.158864110.1116/1.1588641 ↗
21. 10.1002/(SICI)1521-4095(200001)12:1<33::AID-ADMA33>3.0.CO;2-B10.1002/(SICI)1521-4095(200001)12:1<33::AID-ADMA33>3.0.CO;2-B ↗
22. 10.1021/jp980474910.1021/jp9804749 ↗
23. 10.1063/1.150881510.1063/1.1508815 ↗
24. 10.1021/la035634910.1021/la0356349 ↗
25. 10.1002/adfm.20029000910.1002/adfm.200290009 ↗
26. The work function (measured here by a Kelvin probe) varied with the potential drop (ΔV) over the surface dipole layer which is a function of the molecule's dipole moment μ according to ΔV = Nμcosθ/ϵϵ0 whereNis the molecular density of the different derivatives θ is the average tilt of the molecules relative to the surface normal ϵ is the effective dielectric constant of the molecular film and ϵ0is the permittivity of free space. While the relevant dipole moment is that of the molecule bound to the surface this is not trivial to calculate. We used the dipole moment of the free molecule assuming that this will reflect the changes within the series of molecules with identical binding groups.
27. E. H. Rhoderick R. H. Williams Metal–Semiconductor Contacts Clarendon Press Oxford UK1988.
28. 10.1016/S0040-6090(98)00428-310.1016/S0040-6090(98)00428-3 ↗
29. The systematic (molecular) effects found for the Au/dC–X/n‐GaAs (1018 cm–3) junctions together with the fact that the same contacting procedure (ICICE) was used to contact the molecules on the heavily and lightly doped GaAs indicate that the contacting does not significantly damage the molecules below the metal contact.
30. 10.1063/1.34724310.1063/1.347243 ↗
31. 10.1063/1.33205510.1063/1.332055 ↗
32. We compared relative (Γ) rather than absolute (Xpin) values since it is difficult to extract absolute values from FTIR and Kelvin‐probe measurements. To obtain estimates equivalent to Γ from FTIR we integrated the peak of the carboxylate binding group (at ∼ 1650 cm–1) for the different derivatives and divided their magnitudes by each other. We calculated relative molecular densities for the different derivatives from the Kelvin‐probe data by using the relation between ΔVandN which was previously given [25]. The measured electrical potential drops (ΔV) were divided by each other assuming constant tilt angle (because the binding groups were the same) and dielectric constant. The relative molecule density was then extracted by correcting for differences in the dipole moments of the molecules.
33. Hall measurements yieldedNdvalues comparable to those of the original GaAs substrate. This shows that there was no effect of the Au contact and/or the molecules on the bulk doping density of the GaAs substrate.
34. 10.1063/1.32816010.1063/1.328160 ↗
35. Further details on such analysis will be given in a forthcoming paper.
36. We define a negative dipole as one with its negative pole pointing towards the semiconductor substrate.
37. As an internal consistency check we note that the IPE‐derivedXpinvalues for junctions with either negative or positive molecular dipoles did not exceed the upper and lower limits respectively which were derived from theC–Vmeasurements.
38. S. M. Sze Physics of Semiconductor Devices 2nd ed. Wiley New York1981.
39. 10.1103/PhysRevB.54.1028810.1103/PhysRevB.54.10288 ↗
40. 10.1021/la020452k10.1021/la020452k ↗
41. 10.1021/la981426i10.1021/la981426i ↗
42. 10.1016/S0022-0728(00)00424-110.1016/S0022-0728(00)00424-1 ↗
43. H. Haick J. Ghabboun H. Cohen A. Vilan J. Hwang A. Wan F. Amy A. Kahn D. Cahen unpublished.
44. Based on Kelvin‐probe measurements in ultra‐high vacuum and on time‐of‐flight secondary ion mass spectroscopy (TOF SIMS) measurements we found that the conditions used in ICICE had a negligible effect (< 5 %) on the stability of the dC–X molecules adsorbed on GaAs (H. Haick J. Ghabboun M. Ambrico T. Ligonzo D. Cahen unpublished).
45. Positive voltage means that the metal is positive with respect to the semiconductor.
46. 10.1016/S0079-6816(98)00003-310.1016/S0079-6816(98)00003-3 ↗
47. 10.1063/1.35446710.1063/1.354467 ↗