Hello Friends,
We have seen a couple of workings of very commom gadgets in previous posts..so I decided to take a new lane towards technology…
This post is on Nano technology…well, a very promising field at present..so read on to know more
· In 1965, engineer Gordon Moore predicted that the number of transistors on an integrated circuit -- a precursor to the microprocessor -- would double approximately every two years. Today, we call this prediction Moore's Law, though it's not really a scientific law at all.
· To fit more transistors on a chip, engineers have to design smaller transistors. The first chip had about 2,200 transistors on it. Today, hundreds of millions of transistors can fit on a single microprocessor chip. Even so, companies are determined to create increasingly tiny transistors, cramming more into smaller chips. There are already computer chips that have nanoscale transistors (the nanoscale is between 1 and 100 nanometers -- a nanometer is one billionth of a meter). Future transistors will have to be even smaller.
· A nanowire structure has an amazing length to width ratio..Nano wires can be very very thin…It is possible to create a nanowire with a diameter of just one nanaometer.
Human hair is usually between 60 and 120 micrometers wide. Let's assume you have found an exceptionally fine hair with a width of 60 micrometers. A micrometer is 1,000 nanometers, so you would have to cut that hair at least 60,000 times lengthwise to make a strand one nanometer thick.
PROPERTIES OF NANOWIRES:
· Depending on what it's made from, a nanowire can have the properties of an insulator, a semiconductor or a metal.semiconduxtors fall between Metals and Insulators,carrying the charge in right conditions.
· By arranging semiconductor wires in the proper configuration, engineers can create transistors, which either acts as a switch or an amplifier.
· Another interesting property is that some nanowires are ballistic conductors. In ballistic conductors, the electrons can travel through the conductor without collisions. Nanowires could conduct electricity efficiently without the byproduct of intense heat.
· At the nanoscale, elements can display very different properties than what we've come to expect. For example, in bulk, gold has a melting point of more than 1,000 degrees Celsius. By reducing bulk gold to the size of nanoparticles, you decrease its melting point, because when you reduce any particle to the nanoscale, there's a significant increase in the surface-to-volume ratio. Also, at the nanoscale, gold behaves like a semiconductor, but in bulk form it's a conductor. intersting isn’t it?? J
· Another similar example is …In bulk, aluminum isn't magnetic, but very small clusters of aluminum atoms are magnetic.
· Some elements, like silicon, don't change much at the nanoscale level. This makes them ideal for transistors and other applications. Others are still mysterious, and may display properties that we can't predict right now.
HOW NANOWIRES ARE MADE???
· Chemical vapor deposition (CVD) is an example of a bottom-up approach. In general, CVD refers to a group of processes where solids form out of a gaseous phase. Scientists deposit catalysts (such as gold nanoparticles) on a base, called a substrate.
· The catalysts act as an attraction site for nanowire formation. Scientists put the substrate in a chamber with a gas containing the appropriate element, such as silicon, and the atoms in the gas do all the work.
· First, atoms in the gas attach to atoms in the catalysts, then additional gas atoms attach to those atoms, and so on, creating a chain or wire. In other words, the nanowires assemble themselves.
· A new way to build nanowires is to print them directly to the appropriate substrate. A team of researchers in Zurich. First, carved a silicon wafer so that the raised portions on the wafer coincided with the way they wanted the nanowires arranged.
· They used the wafer like a stamp, pressing it against a synthetic rubber called PDMS. They then drew a liquid filled with gold nanoparticles, called a colloidal suspension, across the PDMS.
· The gold particles settled into the channels created by the silicon wafer stamp. Now the PDMS became a mold capable of transferring a "print" of gold nanowires onto another surface. PDMS molds can be used repeatedly and may play a role in the mass production of nanowire circuitry in the future
APPLICATIONS OF NANOWIRE:
· ELECTRONICS: Some nanowires are very good conductors or semiconductors, and their miniscule size means that manufacturers could fit millions more transistors on a single microprocessor. As a result, computer speed would increase dramatically.
· QUANTUM COMPUTERS: A team of researchers in the Netherlands created nanowires out of indium arsenide and attached them to aluminum electrodes. At temperatures near absolute zero, aluminum becomes a supercomputer, meaning it can conduct electricity without any resistance. The nanowires also became superconductors due to the proximity effect. The researchers could control the superconductivity of the nanowires by running various voltages through the substrate under the wires
· NANO ROBOTS: . Doctors could use the nanorobots to treat diseases like cancer. Some nanorobot designs have onboard power systems, which would require structures like nanowires to generate and conduct power.
· GENERATE ELECTRICITY: Using piezoelectric material, nanoscientists could create nanowires that generate electricity from kinetic energy. The piezoelectric effect is a phenomenon certain materials exhibit -- when you apply physical force to a piezoelectric material, it emits an electric charge. If you apply an electric charge to this same material, it vibrates. Piezoelectric nanowires might provide power to nano-size systems in the future, though at present there are no practical applications.
We have seen a couple of workings of very commom gadgets in previous posts..so I decided to take a new lane towards technology…
This post is on Nano technology…well, a very promising field at present..so read on to know more
· In 1965, engineer Gordon Moore predicted that the number of transistors on an integrated circuit -- a precursor to the microprocessor -- would double approximately every two years. Today, we call this prediction Moore's Law, though it's not really a scientific law at all.
· To fit more transistors on a chip, engineers have to design smaller transistors. The first chip had about 2,200 transistors on it. Today, hundreds of millions of transistors can fit on a single microprocessor chip. Even so, companies are determined to create increasingly tiny transistors, cramming more into smaller chips. There are already computer chips that have nanoscale transistors (the nanoscale is between 1 and 100 nanometers -- a nanometer is one billionth of a meter). Future transistors will have to be even smaller.
· A nanowire structure has an amazing length to width ratio..Nano wires can be very very thin…It is possible to create a nanowire with a diameter of just one nanaometer.
Human hair is usually between 60 and 120 micrometers wide. Let's assume you have found an exceptionally fine hair with a width of 60 micrometers. A micrometer is 1,000 nanometers, so you would have to cut that hair at least 60,000 times lengthwise to make a strand one nanometer thick.
PROPERTIES OF NANOWIRES:
· Depending on what it's made from, a nanowire can have the properties of an insulator, a semiconductor or a metal.semiconduxtors fall between Metals and Insulators,carrying the charge in right conditions.
· By arranging semiconductor wires in the proper configuration, engineers can create transistors, which either acts as a switch or an amplifier.
· Another interesting property is that some nanowires are ballistic conductors. In ballistic conductors, the electrons can travel through the conductor without collisions. Nanowires could conduct electricity efficiently without the byproduct of intense heat.
· At the nanoscale, elements can display very different properties than what we've come to expect. For example, in bulk, gold has a melting point of more than 1,000 degrees Celsius. By reducing bulk gold to the size of nanoparticles, you decrease its melting point, because when you reduce any particle to the nanoscale, there's a significant increase in the surface-to-volume ratio. Also, at the nanoscale, gold behaves like a semiconductor, but in bulk form it's a conductor. intersting isn’t it?? J
· Another similar example is …In bulk, aluminum isn't magnetic, but very small clusters of aluminum atoms are magnetic.
· Some elements, like silicon, don't change much at the nanoscale level. This makes them ideal for transistors and other applications. Others are still mysterious, and may display properties that we can't predict right now.
HOW NANOWIRES ARE MADE???
· Chemical vapor deposition (CVD) is an example of a bottom-up approach. In general, CVD refers to a group of processes where solids form out of a gaseous phase. Scientists deposit catalysts (such as gold nanoparticles) on a base, called a substrate.
· The catalysts act as an attraction site for nanowire formation. Scientists put the substrate in a chamber with a gas containing the appropriate element, such as silicon, and the atoms in the gas do all the work.
· First, atoms in the gas attach to atoms in the catalysts, then additional gas atoms attach to those atoms, and so on, creating a chain or wire. In other words, the nanowires assemble themselves.
· A new way to build nanowires is to print them directly to the appropriate substrate. A team of researchers in Zurich. First, carved a silicon wafer so that the raised portions on the wafer coincided with the way they wanted the nanowires arranged.
· They used the wafer like a stamp, pressing it against a synthetic rubber called PDMS. They then drew a liquid filled with gold nanoparticles, called a colloidal suspension, across the PDMS.
· The gold particles settled into the channels created by the silicon wafer stamp. Now the PDMS became a mold capable of transferring a "print" of gold nanowires onto another surface. PDMS molds can be used repeatedly and may play a role in the mass production of nanowire circuitry in the future
APPLICATIONS OF NANOWIRE:
· ELECTRONICS: Some nanowires are very good conductors or semiconductors, and their miniscule size means that manufacturers could fit millions more transistors on a single microprocessor. As a result, computer speed would increase dramatically.
· QUANTUM COMPUTERS: A team of researchers in the Netherlands created nanowires out of indium arsenide and attached them to aluminum electrodes. At temperatures near absolute zero, aluminum becomes a supercomputer, meaning it can conduct electricity without any resistance. The nanowires also became superconductors due to the proximity effect. The researchers could control the superconductivity of the nanowires by running various voltages through the substrate under the wires
· NANO ROBOTS: . Doctors could use the nanorobots to treat diseases like cancer. Some nanorobot designs have onboard power systems, which would require structures like nanowires to generate and conduct power.
· GENERATE ELECTRICITY: Using piezoelectric material, nanoscientists could create nanowires that generate electricity from kinetic energy. The piezoelectric effect is a phenomenon certain materials exhibit -- when you apply physical force to a piezoelectric material, it emits an electric charge. If you apply an electric charge to this same material, it vibrates. Piezoelectric nanowires might provide power to nano-size systems in the future, though at present there are no practical applications.
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