Hydrogen Depassivation Lithography
Hydrogen Depassivation Lithography - Related Videos
07:53
Soft Lithography
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2023
Many BioMEM devices, such as microfluidic channels, are fabricated using the soft lithography technique. Here, a microscale pattern is replicated by curing an elastomeric polymer over the 3D structure. These polymeric structures are then used to create a wide range of devices, ranging from microfluidic channels for biosensing applications to microscale bioreactors for the visualization of micro-colonies. This video introduces photolithography and demonstrates the technique in the laboratory.
06:06
Hydrogenation
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2023
Source: Vy M. Dong and Zhiwei Chen, Department of Chemistry, University of California, Irvine, CA This experiment will demonstrate the hydrogenation of chalcone as an example of an alkene hydrogenation reaction (Figure 1). In this experiment, palladium on carbon (Pd/C) will be used as a heterogeneous catalyst for the process. A balloon will be used to supply the hydrogen atmosphere. Figure 1: Diagram showing the hydrogenation of chalcone to 3-phenylpropiophenone.
10:09
Capillary Force Lithography for Cardiac Tissue Engineering
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Cited by 27 •
2014
In this protocol, we demonstrate the fabrication of biomimetic cardiac cell culture substrata made from two distinct polymeric materials using capillary force lithography. The described methods provide a scalable, cost-effective technique to engineer the structure and function of macroscopic cardiac tissues for in vitro and in vivo applications.
08:21
Fabrication of Periodic Gold Nanocup Arrays Using Colloidal Lithography
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Cited by 1 •
2017
We demonstrate the fabrication of periodic gold nanocup arrays using colloidal lithographic techniques and discuss the importance of nanoplasmonic films.
05:58
Plasma Lithography Surface Patterning for Creation of Cell Networks
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Cited by 16 •
2011
A versatile plasma lithography technique has been developed to generate stable surface patterns for guiding cellular attachment. This technique can be applied to create cell networks including those that mimic natural tissues and has been used for studying several, distinct cell types.
FAQs
A voltage pulse from the conductive scanning tunneling microscope probe breaks selected silicon-hydrogen bonds. This conversion exposes silicon dangling bonds, which are reactive sites that differ chemically from the surrounding hydrogen-covered surface. Because the pulse targets chosen regions, the process translates electrical control from the probe into a localized change in surface reactivity.
Hydrogen remaining outside the exposed regions preserves the passivated character of the surrounding silicon surface. The contrast between hydrogen-covered areas and exposed dangling bonds creates a chemically selective pattern rather than a uniformly reactive surface. That selectivity allows later interactions, such as precursor binding or dopant incorporation, to occur at deliberately positioned sites.
The scanning tunneling microscope provides both a conductive probe and spatial control over where the voltage pulse is applied. This combination lets researchers address selected surface regions individually and create features at near-atomic resolution. The instrument therefore links precise positioning with controlled bond breaking, which is central to forming nanoscale engineering patterns.
Exposed silicon dangling bonds act as reactive attachment sites after hydrogen is removed. Precursor molecules can selectively bind to these locations, while the patterned surface can also guide dopant incorporation. Consequently, the initial lithographic pattern becomes a template for placing material or electrically relevant regions, extending the technique beyond surface modification alone.
The process begins with a hydrogen-terminated silicon surface positioned for scanning tunneling microscope access. A conductive probe is brought to selected regions, where voltage pulses remove hydrogen by breaking silicon-hydrogen bonds. The surrounding passivation remains in place, leaving a designed arrangement of exposed reactive sites that can be used in later fabrication steps.
The patterned sites can support selectively positioned electronic structures and ultra-small devices. Researchers may use exposed regions to bind precursor molecules or to guide dopant incorporation, depending on the intended fabrication route. This makes the technique relevant when device features must be placed with nanoscale precision rather than formed through broad, nonselective surface processing.
Hydrogen depassivation lithography supports semiconductor fabrication by providing controlled patterning at near-atomic resolution. Its ability to define reactive sites also connects surface chemistry with device construction, including research on quantum devices and ultra-small electronic structures. Engineering studies can therefore examine both how patterns are formed and how those patterns direct later material or dopant placement.