Soft-UV Photolithography using Self-Assembled Monolayers

Critchley, Kevin; Zhang, Lixin; Fukushima, Hitoshi; Ishida, Masaya; Shimoda, Tatsuya; Bushby, Richard J.; Evans, Stephen D.

doi:10.1021/jp0630370

Cited by 38 publications

(98 citation statements)

References 54 publications

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“…High purity (99.99%) temper annealed gold wire (0.5 mm diameter) was supplied by Advent. Details of the synthesis of the compounds 1 and 2 used to form SAM1 and SAM2 can be found elsewhere [56].…”

Section: Methodsmentioning

confidence: 99%

“…The second system reported was based on disulphide derivatives that contained nitrobenzyl groups. These were used to form complete SAMs that could be photodeprotected to reveal carboxylic acid groups [56]. Reference 56 provides a detailed characterisation of the latter system using X-ray photoelectron spectroscopy, grazing angle Fourier transform infrared spectroscopy, wetting, and secondary ion mass spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

“…Reference 56 provides a detailed characterisation of the latter system using X-ray photoelectron spectroscopy, grazing angle Fourier transform infrared spectroscopy, wetting, and secondary ion mass spectroscopy. In this study, we present photopatterning techniques using the same disulphide photocleavable derivatives, 1 and 2, as used in [56] figure 1. Compounds 1 and 2 both form SAMs that produce low surfaces energies (with advancing water contact angles of 117 and 112 , respectively).…”

Section: Introductionmentioning

confidence: 99%

“…Compounds 1 and 2 both form SAMs that produce low surfaces energies (with advancing water contact angles of 117 and 112 , respectively). These hydrophobic SAMs (SAM1 and SAM2) can be photo-deprotected using soft UV irradiation to reveal carboxylic acid groups figure 1 [56].…”

Section: Introductionmentioning

confidence: 99%

“…Both SAM1 and SAM2 have similar surface properties after exposure. See [56] for further details of SAM1 and SAM2. Figure 2.…”

Section: Introductionmentioning

confidence: 99%

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Photo-deprotection patterning of self-assembled monolayers

Critchley

Ducker

Bramble

et al. 2007

Journal of Experimental Nanoscience

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Photo-deprotectable self-assembled monolayers (SAMs) provide a versatile platform for creating functional patterned surfaces. In this study, we present nanoscale photo-patterning, multi-component patterning, and a method for producing molecular gradients using photodeprotectable SAMs. Nanoscale patterning of photo-deprotectable SAMs was achieved by coupling a UV laser (365 nm) through a scanning near field probe to produce nanoscale lines of $40 nm, i.e. /9. Multi-component patterning was achieved by a two-stage method combining both microcontact printing and soft-UV photo-patterning. The example demonstrated in this study produced a three-component patterned surface with regions of CF 3 , CH 3 and COOH/ CF 3 functionality. The versatility of these photocleavable SAMs is further demonstrated by creating linear molecular gradients of two functionalities along a distance of $25 mm. The use of 'soft' UV gives several advantages including the ability to pattern SAMs with micron-scale features over large areas quickly, with greater control over the photochemical reactions, and compatibility with existing lithographic facilities thus offering an effective alternative to other patterning methods such microcontact-printing or deep UV patterning.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Both SAM1 and SAM2 have similar surface properties after exposure. See [56] for further details of SAM1 and SAM2. Figure 2.…”

Section: Introductionmentioning

confidence: 99%

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Photo-deprotection patterning of self-assembled monolayers

Critchley

Ducker

Bramble

et al. 2007

Journal of Experimental Nanoscience

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The Motivation for and Challenges to Scaling Down Organic Field‐Effect Transistors

Chan

2019

Adv Elect Materials

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v) operating frequency, [13][14][15] vi) contact resistance, [16][17][18][19] vii) crystallinity and grain boundaries of the organic thin films, [20][21][22] viii) active matrix OFET array or integrated circuit, [23][24][25][26][27][28] ix) novel deposition techniques, [29][30][31][32][33] x) unconventional substrates for OFETs, [34][35][36][37] xi) physical or biological sensors, [38][39][40][41][42][43][44] etc. The progress in all these different aspects has framed the development roadmap of the OFETs. Among all the challenges in the OFET development, some of them are more intricate than the others which deserve the research community to spend more efforts. In this review, I try to discuss the development bottlenecks or limitations in the current OFET research, especially on downsizing. I will also explore some possible direction that can lead to solutions. In the OFET development, the channel carrier mobility (μ) is always considered as the critical parameter to evaluate the overall performance of the devices. The improvement of the dielectric insulators, device structures, or crystallinity of the organic thin films is usually quantified or reflected by the improvements of the mobility values. In some commonly used organic semiconductors, such as pentacene, the variations in the reported mobility values can be up to a few orders of magnitude. Different factors such as the purification level of the semiconductors, fabrication parameters, or processing environments are believed to influence the quality of the OFET active layers and thus the channel carrier mobility. [45][46][47][48][49] Other than these physical components, the way of evaluating the carrier mobility in OFET is equally essential. Erroneous mobility would blur the physics of the device and more importantly, lead to an incorrect conclusion. In general, the carrier mobility in the linear or saturation regime is extracted from the slope of the I D versus V G or I D 1/2 versus V G plot, respectively. The region of the transfer curves used to evaluate the carrier mobility would affect the values significantly. If a kink or change of slope is present in the transfer curves due to the contact resistances, nonequilibrium biasing of shortchannel, minority carrier injection, or other device issues, overestimation of the carrier mobility would result and it has been discussed in the recent work by Gundlach and co-workers, [50] Choi et al., [51] and Okachi. [52] Although the carrier mobility is a significant performance indicator, it should not be considered as the only parameter to access the performances of the OFETs. One major barrier that limits the development of OFET is that the research community too concentrates on the carrier mobility andThe development of organic field-effect transistors (OFETs) in the past few decades has emphasized the carrier mobility of the active layer. It is true that carrier mobility is an important parameter to quantify transistor performance; however, it should not be considered as the only parameter necessary to evaluate ...

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Supported Bilayer Lipid Membrane Arrays on Photopatterned Self‐Assembled Monolayers

Han¹,

Pradeep²,

Critchley³

et al. 2007

Chemistry A European J

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This work demonstrates the use of photocleavable cholesterol derivatives to create supported bilayer lipid membrane arrays on silica. The photocleavable cholesteryl tether is attached to the surface by using the reaction of an amine-functionalized self-assembled monolayer (SAM) and the N-hydroxysuccinimide-based reagent 9. The resultant SAM contains an ortho-nitrobenzyl residue that can be cleaved by photolysis by using soft (365 nm) UV light regenerating the original amine surface, and which can be patterned using a mask. The photoreaction yield was approximately 75 % which was significantly higher than previously found for related ortho-nitrobenzyl photochemistry on gold substrates. The SAMs were characterized by means of contact angle measurements, ellipsometry and X-ray photoelectron spectroscopy. Patterned surfaces were characterized with SEM and AFM. After immersing the patterned surface into a solution containing small unilamellar vesicles of egg phosphatidylcholine (PC), supported lipid membranes were formed comprised of lipid bilayer over the amine functionalized "hydrophilic" regions and lipid monolayer over the cholesteryl "hydrophobic" regions. This was confirmed by fluorescence microscopy and AFM. FRAP studies yielded a lateral diffusion coefficient for the probe molecule of 0.14+/-0.05 microm(2) s(-1) in the bilayer regions and approximately 0.01 microm(2) s(-1) in the monolayer regions. This order of magnitude difference in diffusion coefficients effectively serves to isolate the bilayer regions from one another, thus creating a bilayer array.

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Soft-UV Photolithography using Self-Assembled Monolayers

Cited by 38 publications

References 54 publications

Photo-deprotection patterning of self-assembled monolayers

Photo-deprotection patterning of self-assembled monolayers

The Motivation for and Challenges to Scaling Down Organic Field‐Effect Transistors

Supported Bilayer Lipid Membrane Arrays on Photopatterned Self‐Assembled Monolayers

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