EPSRC Engineering Fellowships for Growth: Narrow Band-gap Semiconductors for Integrated Sensing and Communications

点击翻译按钮获取中文摘要

Semiconductor materials power much of the current economy, through their use in the ubiquitous computer and much else besides. The most common semiconductor is silicon, and this accounts for about 90% of the world market. There are some other types of semiconductor, however, that provide functions that silicon can't address but which are also very important. Examples of these include: gallium arsenide, which is used in satellite receivers and mobile phones for the communications parts; materials based on indium phosphide, which are used in lasers in CD and DVD players and for long distance communications along optical fibres; and materials based on gallium nitride, which are used to make the white light emitting diodes that are now being used for a range of energy efficient lighting and even in car headlights.All of these materials belong to a family known as III-V semiconductors, because they contain a mixture of elements from group 3 and group 5 of the periodic table. III-V semiconductors account for most of the remaining 10% of the electronics industry, and are worth approximately £25bn per year worldwide and growing at about 7%p.a. Unlike the silicon industry, the UK has a significant presence in the manufacture of electronic components based on these materials, as well as systems based upon them, and is in a good position to benefit from the rapid growth in the market.Another member of this III-V semiconductor family in indium antimonide, a compound of indium and antimony, which has the formula InSb. InSb has several interesting properties. Charge carriers can be made to go faster than in any other member of the family and take less voltage to do so. Consequently, this material has the potential to make components that will operate at very high frequencies whilst consuming very little power and so, for example, enable future mobile devices to download massive amounts of data, such as streaming high definition video, without draining the battery or clogging the network. Another application is to enable imaging for detection of illicit explosives or firearms, without use of any harmful radiation. These materials might even find their way into future computers to enable the doubling of computing power to continue every two years, as it has for the last forty years. Other properties of the material mean that we can make infrared sensors for thermal imaging or detection of harmful gases, or photovoltaic devices that would make much more efficient solar energy systems.A corollary of these properties is that heat can cause the materials to "leak" charge, even at room temperature, so currently the only commercial applications are in high performance thermal imaging systems, where the application can tolerate the cost of having to provide cooling to -200C to make them work. This need to cool was previously assumed to be fundamental, however Ashley and co-workers have shown that this is not necessarily the case, and that uncooled operation is possible in several applications. This research will put in place the core technology that would enable a range of devices to be made that will work without any cooling. This technology includes being able to make features on the devices that are more than one thousand times smaller than a human hair and still have the devices operating effectively. It includes the addition of "nano-antennas" to the devices to improve their sensitivity to infrared light by orders of magnitude. It also includes work to show that the devices could be integrated with silicon, to benefit from the system cost savings derived from the massive investment in the silicon industry. The successful outcome of this research would be that various industries in the UK are able to quantify the benefits that the technology offers and make decisions to develop it into products. These would include the sensor manufacturers; prospective new companies in the mobile communications field; and renewable energy community.