Beam Lithography

We mentioned that current light-based industrial lithography is limited to creating features no smaller than the wavelength used. Even though we can in principle get around this restriction by using light of small wavelengths, this solution can generate other problems. Smaller-wavelength light has higher energy, so it can have nasty side effects like blowing the feature you are trying to create right off the surface. (Imagine watering your garden plants with a fire hose.) An alternate way of...

Dip Pen Nanolithography

One way to construct arbitrary structures on surfaces is to write them in exactly the same way that we write ink lines using a fountain pen. To make such lines at the nanoscale, it is necessary to have a nano-pen. Fortunately, AFM tips are ideal nano-pens. Dip pen nanolithography (DPN) is named after the old-fashioned dip pen that was used in schoolrooms in the 19th century. The principle of DPN is shown in Figure 4.3, and the excerpt from Feynman's speech in Figure 4.1 is one DPN-assembled...

Biosensors

Biosensors are not just natural sensors that are part of life they are sensors for biological entities including proteins, drugs, and even specific viruses. Nature does have a variety of schemes for approaching the detection of these entities. One common method is the one behind allergic response. When a body is first exposed to an allergen (a benign substance that it mistakes for a hostile invader), it is sensitized, which means that it creates antibodies that will recognize that allergen if...

Experiment in the Palm of Your Hand Labona Chip

If you read almost any scientific proposal, you will be struck by the amount of money required to pay for two simple but basic needs space and people. Scientific instruments take up a fair amount of space, it's true, but most lab space requirements are taken up by passageways, desks, open surfaces, keyboards, monitors, hoods, emergency equipment, and other necessities for the humans who work there. If you could automate all human tasks in a laboratory and collapse all this space, you could make...

Natural Nanoscale Sensors

As is true with so much of the rest of nanoscience and nanotechnology, examples of sensors at the nanoscale are very widespread in biology. Sensors are crucial to communications, and communication with other organisms is one of the central characteristics of life. Signals come in a variety of formats including molecules, sound, smell, and touch, and they also can come in electromagnetic forms such as heat and light. The ability to detect these signals is both desirable, as in a fragrant...

Tools for Measuring Nanostructures Scanning Probe Instruments

Some of the first tools to help launch the nanoscience revolution were the so-called scanning probe instruments. All types of scanning probe instruments are based on an idea first developed at the IBM Laboratory in Zurich in the 1980s. Essentially, the idea is a simple one if you rub your finger along a surface, it is easy to distinguish velvet from steel or wood from tar. The different materials exert different forces on your finger as you drag it along the different surfaces. In these...

Nanosphere Liftoff Lithography

Nanosphere Lithography

If marbles are placed together on a board as tightly as possible, they will form a tight group, with each marble surrounded by six others. If this array were spray painted from the top, and then the marbles were tipped off the board, the paint would appear as a set of painted dots, each shaped like a triangle but with concave sides see Figure 4.5 . Now if the marbles are nanoscale, so are the paint dots. In fact, Figure 4.5 shows dots of silver metal prepared by Rick Van Duyne's group at...