Nanoscience and ICT

What do the Apollo mission spacecraft to the moon and a washing machine have in common? Same amount of computing power! Technology advances

Module overview Relationship between electric switches and computer bits. Examine what a transistor is. Explore the problems associated with squeezing more electronics into smaller spaces. Examine the role of nanotechnology in this problem. Discuss how nanotechnology is contributing to the development of technologies.

Controlling electrical devices Control electrical devices by switching them on or off. On =1 Off =0 The switch’s two states are represented as a binary number or bit. Bits are arranged into groups of 8 called bytes.

One byte is: A computer instruction. Part of a picture. A keyboard character or symbol. A number.

How a computer uses bytes Storage locations (address) in the memory of a computer contains a byte. Individual bits of each byte are manipulated by transistors.

Transistors A transistor is a semiconductor device that can be used as a switch. Millions of transistors in a computer. Output from each one is a bit. Transistors designed to make a decision on which bit to output depending on the input conditions.

Silicon integrated circuit chip Integrated circuit contains millions of transistors. Greater number of transistors = best performance.

More performance- less space More transistors = more computer brain power. Market demand for smaller, faster devices. Challenge to squeeze as many transistors into as small a space as possible.

Same space- twice the transistors Moore’s law. Number of transistors that can be placed inexpensively on an integrated circuit doubles every two years. Transistors are now constructed at nano-scale size.

Problems with scalability Small diameter of conductor = increased resistance. Difficult for electric current to flow. Laptop gets hot when you use it. Thermal image of Pentium chip operating without a cooling fan.

Problems with scalability Physical properties of some electronic devices change at nanoscale. Below 11 nanometres seems to be the lower limit for transistors to work.

New nano solutions Better design and performance capabilities Nobel Prize in Physics for isolation of a single layer of carbon called graphene.

Graphene

Carbon nanotube properties Excellent conductivity. Not prone to heating. Research at CRANN to determine if they could be used inside transistors. Carbon nanotube forest of height 0.5 mm and width 1 cm. The individual tubes are approximately 15 nanometres in diameter. Image captured in CRANN using Ultra SEM.

Milestones in nanotechnology Flash Memory Does not require moving parts. Small. Portable. Durable.

Milestones in nanotechnology GMR- Giant Magnetoresistance. Very weak magnetic changes = major differences in electrical resistance. Allows more data to be packed on computer disks. Increase efficiency and safety of home appliances, transport and factories.

The past and present ThenNow The IBM 305 RAMAC Computer was introduced in 1956 and had world's first hard disk drive. It could hold 4.4 MB (1 song). It cost $160,000 in todays money. A standard desktop today costing about 700 euro contains a hard disk that can hold 1TB- (250,00 songs). The first commercial text message was sent by Nokia in The number of text messages sent in 2010 exceeded the population of the planet 328 times. The number of internet devices in 1984 was There was 1 billion internet devices in In the 1960s, voice calls began to be digitized. Digital voice signals can share the same wire with many other phone calls. NTT Japan can pass 14 trillion bits per second down a single optic fibre cable-2660 cds every second.

The future? Quantum computing uses the spin on electrons instead of current. Molecular self-assembly. Smaller magnetic devices.

Electronic paper Future is digital media. Oled; graphene; silver nanowires. Flexible, transparent and strong. Silver nanowires used to create thin, flexible, transparent, conducting films.

3-D holographic displays Holographic displays Transparent screens

Future of portable digital devices? Morphing devices Nokia morph phone: –Flexible and shape changing. –Transparent. –Self-cleaning. –Solar energy to recharge battery. –Fully integrated sensors.

Future applications of graphene

Summary Relationship between electric switches and computer bits. Transistors and ICs. Problems associated with squeezing more transistors onto ICs. The role of nanotechnology in this problem. Future devices.