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The purpose of this new book is to show the main techniques and strategies needed to design and model simple and complex photonic devices, which can be used for telecommunications, signar processing or sensing applications. In fact, the modeling approaches and techniques of photonic devices are not

Molecular electronics is an exciting and challenging sphere of activity, enabling the fabrication of a wide range of electronic devices based around organic materials and lowcost technologies. Taken to its limit, molecular electronics also offers unlimited computational power. However, the subject is not without its critics, who are quick to point out that organic materials have restricted stability and will find difficulty competing with their inorganic counterparts. The International Semiconductor Roadmap also predicts that silicon microelectronics still has some way to go before it runs out of steam. Supporter or sceptic – much depends on your definition of molecular electronics. Are we dealing with materials science or molecular manipulation? The purpose of this book is to provide some clarity here. My intention is first to give some insight into the physics and chemistry of organic materials, and to explore the means that are now available to manipulate these materials and to measure their properties. An overview is then provided of what already has been achieved, in terms of technological applications, and what may be accomplished in the foreseeable future. I have written the book from the viewpoint of a finalyear science or engineering undergraduate; I hope it is accessible to readers from a wide range of backgrounds. Examples of ‘applications’ have been taken from the portfolio of molecular electronics research that was available as this book was being written (2006) – not because I am convinced that they will all definitely become future technologies (many certainly will not) but because these form a vision of molecular electronics and indicate important directions in research. Some of the current activity in molecular electronics (or plastic electronics, as many refer to it) is focused on replacing the silicon and other inorganic semiconductors, which are currently used in devices, with organic materials. The motivation is the reduced cost and large-area capability of organic thin film technologies. Over the last 30 years, tremendous progress has been achieved. However, much more of the work demonstrated in the laboratory needs to be translated into reliable and reproducible products, which can be manufactured cheaply. The path towards molecular-scale electronics will probably be found in other directions. In particular, I believe that valuable lessons can be taken from the natural world. I have therefore included a final chapter in this book on the topic of bioelectronics. However, can anyone really predict the future? Growing up in the UK in the 1960s, Thursday evenings were special. On BBC television, there was ‘Top of the Pops,’ and before this, ‘Tomorrow’s World’. The host was Raymond Baxter, a genial ex-RAF man and qualified Spitfire pilot. He spoke eloquently and with great authority on the technology to come. He broadcast from Concorde in its early days and he introduced us to the pocket calculator, microwave oven and the barcode (but curiously did not foresee the Internet). In several programmes, predictions were made on the development of household appliances. By the end of the 20th century, our houses would be run by robots, Raymond informed us confidently. These metal and plastic creatures would wander around doing all the household chores such as cleaning, vacuuming, gardening and cooking. We know this did not happen, but not for the problems with developing the technology. After all, Neil Armstrong stepped on to the surface of the Moon in 1969 and unmanned spacecraft have landed on Venus and Mars. The explanation lies in a mixture of politics and cost: apart from what is technically feasible, political and economic matters can play an important role in the progress of technology. Environmental issues will certainly have an increasing influence on the developments in the 21st century. So, be wary of predictions of nano-robots wandering around your bloodstream (we already have these anyway – in the form of bacteria). I suspect that the future will reveal things that are far more intriguing.