Germanium: giving microelectronics an efficiency boost

Abstract

Introduction Germanium is a rare element but is present in trace quantities in most rock types because of its affinity for iron- and organic-bearing materials. The average germanium content of the Earth is about 14 parts per million, but the majority of germanium resides within the Earth’s core (37 parts per million) while the Earth’s crust contains only about 1.5 parts per million. Germanium does not occur as a native metal in nature, but about 30 different germanium minerals are known to exist. In refined form, it is grayish-white and metallic in appearance. Germanium is a semiconducting metalloid with electrical properties between those of a metal and an insulator. Germanium was discovered in the late 1800s within silver ore at a mine near Freiberg, Germany. The German chemist who described the element, Clemens Winkler, named it germanium, after his native country. More than half a century elapsed before its first commercial use after World War II, when Karl Lark-Horovitz from Purdue University discovered its properties as a semiconductor. Today germanium is commonly used in commercial, industrial, and military applications. Germanium is an essentially nontoxic element, with the exception of only a few compounds. However, if dissolved concentrations in drinking water are as high as one or more parts per million chronic diseases may occur.