Karl Baedeker (physicist)

Karl Baedeker (1910)

Karl Wilhelm Sali Baedeker (born February 3, 1877 in Leipzig ; † August 6, 1914 near Liège ) was a German physicist and associate professor at the Friedrich Schiller University in Jena . The discovery of the doping of semiconductors is attributed to him .

Life

Born as the son of the publisher Fritz Baedeker , Karl Baedeker attended the humanistic Thomas School in Leipzig from 1886 to 1895 .

After graduating from high school, Baedeker studied chemistry , mathematics and physics at the University of Geneva , the Ruprecht-Karls-University of Heidelberg , the Ludwig-Maximilians-University of Munich and at the Georg-August-University of Göttingen . It was 1900 in Göttingen during the later Nobel laureate Walther Nernst with the thesis experimental study on the dielectric constant of some gases and vapors in their function of temperature for Dr. phil. PhD.

Then Baedeker worked for Otto Wiener in Leipzig. For eight weeks he was assistant to Wilhelm Wien at the Julius Maximilians University of Würzburg and for two years second assistant to Walter König at the Ernst Moritz Arndt University of Greifswald . From April 1905 he worked again in Leipzig.

In 1907 Karl Baedeker married Katharina (Käthe), b. Fielitz from Greifswald. Two children were born to you.

In 1907 Baedeker completed his habilitation in physics at the University of Jena with a thesis prepared by Theodor des Coudres at the University of Leipzig . In 1910 he was appointed associate professor for physics in Jena .

Baedeker fell on August 6, 1914, shortly after the beginning of the First World War , as first lieutenant in the reserve of field artillery and brigadjutant during the advance of the 14th Infantry Brigade between Fort Fléron and Fort Evegnée ( conquest of Liège , battle for Fort Fléron in Rétinne ) the side of General Friedrich von Wussow and Colonel Alfred Gustav Krüger. He was 37 years old. Karl Baedeker's final resting place is the German military cemetery in Vladslo (Block 9, grave 1577) after being reburied several times .

science

His main areas of work were based on physical chemistry , questions of electrical conduction in metals and thermoelectricity . As early as 1907, he observed that the conductivity of transparent copper iodide layers ( insulators or semiconductors ) increases by orders of magnitude when additional iodine is introduced into the crystal by diffusion . He also reports on the good electrical conductivity of transparent (orange-yellow colored) cadmium oxide layers and thus the first transparent conductive oxide layer . He observes a positive Hall constant on the CuI and a negative Hall constant on the CdO . Only later could it be understood that CuI is p-conducting and CdO is n-conducting. That counts as the discovery of the defect electrons .

Fonts (selection)

• Experimental investigation of the dielectric constant of some gases and vapors as a function of temperature. W. Engelmann, Leipzig 1900. (= also dissertation, University of Göttingen 1900)
• About the electrical conductivity and thermoelectric power of some heavy metal compounds. In: Annalen der Physik 327 (1907) 4, 749-766. doi : 10.1002 / andp.19073270409 (= also habilitation thesis, University of Jena 1907)
• The electrical phenomena in metallic conductors. F. Vieweg, Braunschweig 1911.

literature

• Felix Auerbach : Karl Baedeker. In: Physikalische Zeitschrift 15 (1914), 901–902.
• Walter Kaiser: Karl Bädeker's contribution to semiconductor research. In: Centaurus 22 (1978) 3, 187-200. doi : 10.1111 / j.1600-0498.1979.tb00588.x
• Franz Bolck (Ed.): Physics section - on the development of physics after 1945 at the Friedrich Schiller University Jena. Jena 1982. (= Jena speeches and writings 1982)
• Marius Grundmann: Karl Bädeker (1877-1914) and the Discovery of Transparent Conductive Materials. In: Physica Status Solidi A 212 (7), 1409-1426 (2015). doi : 10.1002 / pssa.201431921

Web links

• Literature by and about Karl Baedeker in the catalog of the German National Library
• Baedeker, Karl ( Memento from June 14, 2007 in the Internet Archive ) (PDF) in the professors' gallery of the Physics and Astronomy Faculty in Jena

Individual evidence

1. ↑ Nuclear Physics at the Friedrich Schiller University Jena from 1946 to 1968 ( Memento of the original from August 24, 2011 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. 
2. ↑ Gottlieb Tesmer, Walther Müller: Honor roll of the Thomas School in Leipzig. The teachers and high school graduates of the Thomas School in Leipzig 1912–1932. Commissioned by the Thomanerbund, self-published, Leipzig 1934, p. 1.
3. ↑ Richard Sachse , Karl Ramshorn, Reinhart Herz: The teachers of the Thomasschule in Leipzig 1832-1912. The high school graduates of the Thomas School in Leipzig 1845–1912 . BG Teubner Verlag, Leipzig 1912, p. 91.
4. ↑ ^{a b} Family tree Baedeker family (Karl Baedeker, Coblenz) , accessed on November 5, 2014.
5. ↑ Elektrotechnische Zeitschrift, vol. 35 (1914), p. 966.
6. ↑ Physikalische Zeitschrift, vol. 16 (1915), p. 142.
7. ^ Gustave Somville: Vers Liége. Le chemin du crime . Août 1914. Perrin, Paris 1915
8. ↑ Volksbund Deutsche Kriegsgräberfürsorge (accessed December 6, 2017)
9. ↑ Biographical Notes on Robert Wichard Pohl, pdf , University of Göttingen 2013, Interview Pohl, Heinz Pick, p. 19. According to Pohl's memory, he initially did not take the work from 1911 seriously because he thought Baedeker had used aqueous solutions.