Near-surface electronic structure in GaAs (100) modified with self-assembled monolayers of octadecylthiol

Dorsten, J. F.; Maslar, James E.; Bohn, Paul W.

doi:10.1063/1.113357

Cited by 54 publications

(62 citation statements)

References 17 publications

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“…9 It is believed that the sulfur to GaAs bond provides passivation comparable to that observed in studies involving elemental sulfur, with additional stability provided both by the characteristics of the LTG:GaAs and the organic tail of the XYL molecule. [23][24][25] A patterned XYL layer has been used as an etch mask for wet chemical etching of the GaAs layers by covering these molecules in certain areas of the sample surface. 26…”

Section: Metal/molecule/semiconductor Nanostructuresmentioning

confidence: 99%

Self-assembled metal/molecule/semiconductor nanostructures for electronic device and contact applications

Janes

Lee

Liu

et al. 2000

Journal of Elec Materi

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We report a fabrication approach in which we combine self-assembled metal/ molecule nanostructures with chemically stable semiconductor surface layers. The resulting structures have well controlled dimensions and geometries (~ 4 nm Au nanoclusters) provided by the chemical self-assembly and have stable, low-resistance interfaces realized by the chemically stable semiconductor cap layer (low-temperature grown GaAs passivated by the organic tether molecules). Scanning tunneling microscope imaging and current-voltage spectroscopy of nanocontacts to n-GaAs fabricated using this approach indicate high quality, ohmic nanocontacts having a specific contact resistance of ~1 ¥ 10 -7 W · cm 2 and a maximum current density of ~1 ¥ 10 7 A/cm 2 , both comparable to those observed in large area contacts. Uniform 2-D arrays of these nanocontact structures have been fabricated and characterized as potential cells for nanoelectronic device applications.

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Section: Metal/molecule/semiconductor Nanostructuresmentioning

confidence: 99%

Self-assembled metal/molecule/semiconductor nanostructures for electronic device and contact applications

Janes

Lee

Liu

et al. 2000

Journal of Elec Materi

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“…1 It is believed that the sulfur to GaAs bond provides passivation comparable to that observed in studies involving elemental sulfur, with additional stability provided both by the characteristics of the LTG:GaAs and the organic tail of the XYL molecule. [5][6][7] A patterned XYL layer has been used as an etch mask for wet chemical etching of the GaAs layers by covering these molecules on a certain area of the sample surface. 8 A copy ͑STM͒ was used to locate and probe the electronic properties of the nanocontacts.…”

Section: ͓S0003-6951͑00͒03002-3͔mentioning

confidence: 99%

Ohmic nanocontacts to GaAs using undoped and p-doped layers of low-temperature-grown GaAs

Lee

Chen

Liu

et al. 2000

Applied Physics Letters

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The development and characterization of high-performance nanocontacts to n-GaAs are reported. The nanocontacts can be made to both undoped and p-doped low-temperature-grown GaAs ͑LTG:GaAs͒ cap layers. The geometry of the nanocontact is well characterized and requires the deposition of a 4 nm single-crystalline Au cluster onto an ohmic contact structure which features a chemically stable LTG:GaAs surface layer prepared using an ex situ chemical self-assembly technique. A self-assembled monolayer of xylyl dithiol (HS-CH 2 -C 6 H 4 -CH 2 -SH) is required to provide mechanical and electronic tethering of the Au cluster to the LTG:GaAs surface. For the case of an undoped LTG:GaAs cap layer, a specific contact resistance of 1ϫ10 Ϫ6 ⍀ cm 2 and a current density of 1ϫ10 6 A/cm 2 have been measured from scanning tunneling microscopy. When a p-doped LTG:GaAs cap layer is used, the corresponding values are 1ϫ10 Ϫ7 ⍀ cm 2 and 1 ϫ10 7 A/cm 2 , respectively. Improved surface stability as evidenced by a lower oxidation rate for p-doped LTG:GaAs provides a natural explanation for the higher-quality ohmic contact properties of the nanocontact to the p-doped LTG:GaAs cap layer.

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“…The inherent ability of adsorbed monolayers to modify the physical and chemical properties of solid surfaces makes them attractive for the effective control of III-V semiconductors. [13][14][15][16][17][18][19] Hence, it has become increasingly imperative to accurately determine the stability of SAMs prepared a͒ Electronic mail: lapierr@mcmaster.ca by various methods, as well as to develop a better understanding of the reasons underlying the discrepancy in the reliability of the ensuing passivation. 10 Consequently, this novel passivation mechanism has demonstrated its relevance as a prospective means of preventing further chemical modification while at the same time maintaining the desired electronic properties of the underlying surface, especially in the case of nanoscale device structures for which there is a large surface-to-volume ratio.…”

Section: Introductionmentioning

confidence: 99%

Passivation of GaAs by octadecanethiol self-assembled monolayers deposited from liquid and vapor phases

Budz

Biesinger

LaPierre

2009

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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Fourier-transform infrared and photoluminescence spectroscopies of self-assembled monolayers of long-chain thiols on (001) GaAs J. Appl. Phys. 99, 054701 (2006); 10.1063/1.2178659Passivation of InP surfaces of electronic devices by organothiolated self-assembled monolayers Self-assembled monolayers ͑SAMs͒ of octadecanethiol ͑ODT͒, CH 3 ͑CH 2 ͒ 17 SH, were deposited on GaAs ͑100͒ substrates from liquid and vapor phases. Liquid-phase-deposited SAMs were prepared by immersing the substrate in a dilute solution of ODT and ethanol, while vapor-phase-deposited monolayers were prepared by exposing the GaAs surface to a stream of ODT vapor in an ultrahigh vacuum environment. The structural and optical properties of the resulting SAMs were examined with contact angle ͑CA͒ analysis, photoluminescence ͑PL͒ spectroscopy, high-resolution x-ray photoelectron spectroscopy ͑HRXPS͒, and spectroscopic ellipsometry. Although well-ordered films were formed from both deposition techniques, PL, CA analysis, and ellipsometry measurements revealed that the overall quality, structure, and long-term durability of the resulting SAMs depended on the preparation method. Specifically, time-dependent PL and CA analysis indicated an enhanced stability for vapor-deposited films stored under ambient conditions. Through HRXPS measurements, the attachment of the thiolate molecules to the GaAs substrates was shown to proceed through the formation of chemical bonds at both Ga and As surface sites, with the percentage of each bonding configuration dictated by the surface termination produced via the cleaning process used prior to the SAM deposition. Collectively, the results suggested that more robust monolayers exhibiting greater surface coverage, and therefore increased passivation and stability characteristics, are assembled from vapor phase.

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Near-surface electronic structure in GaAs (100) modified with self-assembled monolayers of octadecylthiol

Cited by 54 publications

References 17 publications

Self-assembled metal/molecule/semiconductor nanostructures for electronic device and contact applications

Self-assembled metal/molecule/semiconductor nanostructures for electronic device and contact applications

Ohmic nanocontacts to GaAs using undoped and p-doped layers of low-temperature-grown GaAs

Passivation of GaAs by octadecanethiol self-assembled monolayers deposited from liquid and vapor phases

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