Professors Margit Härting and David Britton at the University of Cape Town in South Africa have been working on the printing of nano silicon electronic components in parallel with Kovio in California and others.
The attraction of nanosilicon is that it can be printed by a variety of printing technologies and both p type and n type semiconductors are relatively easy to produce. By contrast, n type organic printed semiconductors and p type zinc oxide semiconductors are problematical. Another advantage lies in the much higher charge carrier mobility of silicon nano particles compared with these alternative - typically a magnitude above ZnO based formulations and two or three magnitudes better than organic semiconductors. For more details see the video clip below.
Kovio is ahead in commercialisation of printed nanosilicon transistors, having made complex analog digital HF RFID with 1000 transistors last year to ISO 14443. IDTechEx has tested these remarkable devices and been very impressed. However, because of high temperature annealing, Kovio prints on stainless steel foil. This is not a great problem on the cost front but could be a challenge with metal detectors on food production lines and in some other situations.
Professors Härting and Britton have progressed to printing nanosilicon on low cost plastic film and even on paper, opening up new markets, for example for biodegradable, environmental electronics. They will seek to commercialise thermistors then transistor circuits using this technology.
There are many other opportunities. For example, Innovalight raised $18 million in 2010 to further commercialise its process that coats conventional silicon solar cells with printed nanosilicon to improve performance.
The professors have won an IDTechEx award for their work and they are now spinning out a nanosilicon printed electronics company and setting up a Nanosciences Innovation Centre.
Patents on this work include 20090092855 Doping of particulate semiconductor materials 04-09-2009
For more attend: Printed Electronics USA 2010.