Monday, August 19, 2013

Germanium: Most Scientific Member of the Periodic Kingdom?

Even though it has been superseded in its importance in the solid state electronics industry by its more regal sibling named silicon, is germanium nonetheless the most scientifically active member of the periodic kingdom? 

By: Ringo Bones

Even though germanium was the first semiconductor used when the first solid state transistors first went into commercial production in the middle of the 1960s because it was then easier to “dope” than its silicon sibling – i.e. the iconic Mullard AD 149 PNP germanium transistor from the Golden Age of Stereo – the element has since been relegated for more serious scientific endeavors as opposed to the glamour of the consumer electronics industry. But first, here’s an introductory curriculum vitae of the element germanium.
Germanium, chemical symbol Ge, is a metallic chemical element. It is a member of the carbon family, which also includes carbon, lead, silicon and tin. Germanium was discovered by Clemens Winkler in 1886 – 14 years after Dmitri Mendeleev had predicted its existence via his periodic table of the elements and called it eka-silicon. Its primary use is in transistors and in the current solid state electronic microchip industry in conjunction with silicon. Germanium is found in many sulfide ores, especially those of silver, lead, tin, zinc and antimony. Germanite is a complex sulfide of copper, iron, zinc and lead which contains 5 to 8 percent germanium; argyrodite is a silver sulfide with 5 to 7 percent germanium. The main commercial source of germanium is the cadmium fume dust obtained in sintering zinc concentrates. The world’s leading producers of germanium are Belgium, Japan and South-West Africa. 

Germanium is found in Group IV-A of the periodic table, falling between silicon and tin. Germanium is a grayish white, hard and brittle. It is a semiconductor and is used in transistors, tunnel diodes and in germanium rectifiers. Germanium is stable in the air and resists the action of acids and bases. It has a valence of +4 and +2 in its compounds, which resemble those of tin. 

One of the first serious scientific utilization of germanium happened near the end of the 1960s when Professor Frank J. Low of the University of Arizona developed a device called a germanium bolometer. The devices heart consists of a tiny germanium crystal that is cooled with liquid helium to turn it into a very sensitive thermometer. The germanium bolometer was first tested on a University of Arizona astronomical telescope with a 60-inch parabolic mirror to enable it to detect very weak infrared radiation given of by distant celestial bodies. The telescope’s mirror focuses the gathered infrared radiation on a detector - called a germanium bolometer - that precisely measures planetary temperatures elsewhere in our Solar System that’s millions of miles away. The instrument is able to detect a hundred-trillionth of a watt of infrared radiation – equivalent to sensing the heat given off of a lighted cigarette 10,000 miles away. 

In our current scientific hunt for that elusive “substance” that makes up over 90 percent of the whole Universe and yet we cannot even see or sense it with our unaided senses called dark matter, we had called on the help from germanium. A cylinder of ultrapure germanium cooled to near absolute zero and stored 5 miles underground and shielded against stray background radiation that might skew the results – is the latest serious scientific set-up - a “germanium dark matter trap” if you will – is now used to capture the evidence that might finally prove beyond the shadow of the doubt confirm the existence of dark matter.