The following article sheds a light on the topic of nanotechnology, especially nanosensors and nanofabrication.
What is nanotechnology?
The study and understanding on extremely small structures reaching to one tenth of a nanometer is referred to as “nanotechnology.” The word “nano”, as you may have guessed by now, in itself means “small”. A nanometer is one billionth of a meter. To be able to get a better understanding of it, one nanometer is 100,000 times smaller than the width of an average human hair.
Nanotechnology guides us to see and manipulate atom and molecules. We come across nanotechnology in our routine life almost everyday, with projectors, computer and mobile processors, and various other things made possible with the power of nanotechnology. It contributes to many fields in science including medical, transportation, electronics, energy and environment and even space exploration.
Nanosensors
In order to detect the presence of nanoparticles, or alter the physical specifications (for example temperature), chemical or mechanical sensors known as “nanosensors” are used.
Uses/Applications-
Nanosensors have various uses. For example,
· They are used to study and monitor physical parameters such as temperature.
· They can also be used to detect the chemicals present inside a gas, which can be used to monitor pollution.
· Nanosensors are used to get a deeper understanding of neurotransmitters present in the brain to study neurophysiology.
Working of a nanosensor
Most nanosensors can convert the observed material or a process into electrical signals. Nanosensors basically work by monitoring electrical charges in the sensor materials. Nanosensors can be chemical sensors or mechanical sensors.
For example, if a molecule of nitrogen dioxide comes in contact with a chemical carbon tube nanosensor, it will strip an electron from the nanotube (nanomaterial), which will make the nanotube less conductive. The nanotube will notice this and send electrical signals. Nanosensors detect changes from the external interactions and communicate to the other nanocomponents.
Nanosensors have been developed to the point of measurement at the single molecule level.
How nanosensors are made- nanofabrication
The design and manufacture of devices with dimensions measured in nanometers (nanosensors) is called nanofabrication.
Nanofabrication can be practiced in various major ways. The most widely used method is known as top down fabrication. The most common top down fabrication technique is nanolithography. In lithography, the material required in order to complete the nanostructure is protected by a mask, and the material that has been exposed is etched out. There are a few different methods to etching. Etching can be done chemically with the help of acids, or mechanically with ultraviolet rays (UV rays), x-rays or electron beams. Most, if not all top down fabrication methods involve etching at some stage.
The major drawbacks/demerits of nanofabrication
However seemingly perfect anything may be, everything is packed with a few flaws. Nanofabrication is no exception in this case. Top down is a very efficient method and takes relatively less time, but the it comes with a huge price. Literally. The equipment needed for this method is nowhere near what an average man could afford. It is very expensive. Another method of nanofabrication, bottom up method, is lower costing, but isn’t currently effective and takes much longer than top down fabrication method.
Ideas to improve nanofabrication
Scientists from all over the world are currently working on making the top down method more convenient by making it self- assembling, but there are significant hurdles that need to be overcome in order for that to happen. Another way to improve the process of nanofabrication is finding better and alternative materials through which the process can take place.
Thank you.
-Atif Raza.