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<p>Semiconductor physics is not just about shrinking transistors. Other major challenges would include the exploration of development of semiconductors on materials other than traditional crystalline silicon, as those other materials have certain properties that may make them superior to silicon for certain applications. For example, we already use gallium-arsenide semiconductor devices in wireless communications (i.e. cellphone, satellite) because Ga-As has superior signal-to-noise and can function at higher frequencies than can silicon. It also may have superior characteristics for use in lighting, i.e. to create energy-efficient LED’s that can replace incandescent light bulbs. Crystalline germanium may offer superior properties in capturing energy in photovoltaic cells and hence provide a breakthrough to cheap solar power. Surely researchers will explore other interesting properties of and create devices from other semiconductor materials. </p>
<p>You can also formulate and develop entirely new types of semiconductor devices. For example, just a few months ago, researchers at HP Labs published in Nature the creation of the world’s first true memristor, which had previously existed only in theory. This is a revolutionary advance in electrical engineering because now rather than having just the basic 3 circuit building blocks: the resistor, capacitor, and inductor, you now have a 4th. Although the HP memristor in question is purely experimental at this point (and hence very slow and expensive), surely, much effort will be spent in understanding how to commercialize them and how to use them to create more complicated systems. </p>
<p>[Engineers</a> find ‘missing link’ of electronics - tech - 30 April 2008 - New Scientist Tech](<a href=“http://technology.newscientist.com/article/dn13812-engineers-find-missing-link-of-electronics.html]Engineers”>http://technology.newscientist.com/article/dn13812-engineers-find-missing-link-of-electronics.html)</p>
<p>But there’s also a general point that you need to consider. Getting a PhD in a particular subfield doesn’t mean that you’re going to be pursuing that specific subfield for the rest of your life. You are going to need to be flexible. Technology will change and you will need to change with it. For example, during the early days of the computer industry, most of the engineers were obviously not trained as computer engineers or computer scientists because, by definition, those subfields didn’t even exist at the time. Instead, the early computer hardware industry drew from engineers whose expertise lay in vacuum tubes for radio, television, radar, and so forth. The software industry drew from mathematicians who devised algorithms and devised the computability/complexity theory. Hence, you have to be willing to be flexible in your career to accommodate whatever new technology is developed. For example, what if you were one of those guys who had gotten a PhD specializing in radio tubes for the radio industry and simply decided to ignore the transistor? You would have been similarly out of a job. But if you had transferred to the burgeoning computer industry, you would have been able to update your skills. </p>
<p>Everybody has to face the problem of technical obsolescence. Not just people with PhD’s, but everybody. Secretaries who knew only typewriters and who refused to learn word processing software lost their jobs. The real point is to be flexible in your career and be constantly updating your skills.</p>