Week 9 Emerging Technologies Neuroprosthetics Week 9 Emerging Technologies

Emerging Technologies Neurotechnology:Microelectronics Molecular and Nanoscale electronics

Microelectromechanical Systems (MEMS) Goals and Requirements Reduce/Eliminate interconnecting leads Distribute intelligence Minimize power consumption Minimize device area (volume) Improve reliability and longevity of implants

Molecular Electronics Molecular materials for electronics – electronic devices using organic compounds e.g. liquid crystal displays Molecular scale electronics – size reduction in individual processing elements

Molecular Materials Plastic Electronics Organic light-emitting structures Chemical sensors

Plastic Electronics Organic semiconductors low cost New materials with different bandgaps Simple fabrication for polymers Organic thin-film transistors key for plastic circuitry as display drivers in computers, as memory elements and ID tags

Organic Light-Emitting Structures Organic Light Emitting Devices (OLEDs) based on polymer p-phenylene vinylene (PPV) Organic semiconductor sandwiched between low and high electrodes – when voltage applied, electrons are injected from one electrode and holes from the other Recombination – light emission Low molecular weight organic molecules and polymers

Chemical Sensors Growing need for identification of chemical & biochemical substances Usually (Oxide) sensors must be operated at high temperatures Organic substances – high sensitivity to gas Can be tailored to an application by modification of their structure Array of sensors (electronic nose) to improve on sensitivity

Molecular Scale Electronics Molecular superlattices Single electron devices DNA electronics

Molecular Superlattices Pyroelectric devices good as detectors of infrared – efficient at ambient temps. Pyroelectric – noncentrosymmetric crystal structure + thin-film fabricated Grow thin polycrystalline film (ceramic) then apply large electric field – RF Sequential layer build up enables unique polar structure

Single Electron Devices Current flow determined by tunnelling through energy barriers Structures of less than 10nm Nanoparticles form FET – by sensing current difference between 2 states so the stored information can be read Quantum effects become important (Quantum computing)

DNA Electronics DNA deemed to be a molecular wire of very small resistance DNA – most significant molecule in nature! Charge carriers can shuttle (tunnel) along a DNA molecule for a few nm DNA chips – short strands of DNA bind to others – can probe if certain genetic codes are present or absent Data can be stored - DNA 1 bit in 1 nm3 DRAM 1 bit in 1000000000000 nm3

Final Words Organic compounds attractive for electronic devices Living systems assemble themselves from molecules – energy efficient But extremely speculative at this stage Most likely niche areas – infrared detection for example