The End of Silicon May Be in Sight

''Gallium (especially gallium arsenide, known to chemists as GaAs) has been studied for three decades as a replacement for silicon, since its higher "electron mobility" should produce faster transistors and therefore faster computers, explained Christopher Hinkle, a materials scientist at the University of Texas. This is especially true of a three-way combination of indium (a rare, silvery metal), gallium (another rare silvery metal that in pure form melts at room temperature), and arsenic (a notorious poison that can also serve as a hardening agent).'' [source]