Hsu Yun Fan
Honorary Degree Recipient
- Doctor of Science, Purdue University 1990
Professor Fan had a distinguished undergraduate education in China and graduate education in MIT where he received a Sc. D. degree in 1937 working with Professor von Hippel. From 1937-1949 he worked at the National Tsing Hua University starting as an assistant professor, becoming professor in 1939. This was a politically turbulent period with China suffering a massive Japanese aggression. Fan carried on his teaching and research and managed to publish several papers on the physics of electrical contact between a metal and a semiconductor; photoelectric and thermoelectric emission from metals; and the theory of rectification of an insultating layer. This period, overlapping the second world war, must be viewed as "heroic", considering the extraordinary physical and political circumstances under which he managed to function as a scholar and a researcher.
In 1949, after a short interlude at MIT, Fan was attracted to Purdue by Karl Lark-Horovitz. He was rapidly promoted to full professor position by 1951. In 1963 he became The Duncan Distinguished Professor, a position he occupied until he retired in 1978.
During the 1950's and 1960's, when semiconductor physics emerged as a major discipline in condensed matter physics and its impact was felt in both basic science and in device technology, Fan made many landmark discoveries:
- Infrared transparency, absorption edge, and nature of the valence and conduction bands of silicon and germanium.
- Free carrier absorption in n- and p- type germanium and the complex nature of the valence band of germanium.
- Temperature and pressure dependence of the energy gap of semiconductors.
- Plasma edge associated with free carriers and optical determination of effective masses.
- Radiation damage - defects produced by neutron, electron and deuteron irradiation and infrared absorption due to their electronic and vibrational excitations.
- Infrared absorption and photoconductivity associated with the localized electronic levels of donors and acceptors in germaniun and their Zeeman effect.
- Lattice vibrations in covalent and ionic semiconductors.
- Oscillatory photoconductivity in 111-V semiconductors.
- Recombination radiation from Ill-V semiconductors.
- Excitonic absorption in 111-V semiconductors. There is hardly any branch of semiconductor physics to which Fan did not make a significant contribution.