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Docket #:

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To the proposer’s knowledge, is this achievement subject to litigation? No

Is the achievement you are proposing more than 25 years old? Yes

Is the achievement you are proposing within IEEE’s designated fields as defined by IEEE Bylaw I-104.11, namely: Engineering, Computer Sciences and Information Technology, Physical Sciences, Biological and Medical Sciences, Mathematics, Technical Communications, Education, Management, and Law and Policy. Yes

Did the achievement provide a meaningful benefit for humanity? Yes

Was it of at least regional importance? Yes

Has an IEEE Organizational Unit agreed to pay for the milestone plaque(s)? Yes

Has an IEEE Organizational Unit agreed to arrange the dedication ceremony? Yes

Has the IEEE Section in which the milestone is located agreed to take responsibility for the plaque after it is dedicated? Yes

Has the owner of the site agreed to have it designated as an IEEE Milestone? Yes

Year or range of years in which the achievement occurred:


Title of the proposed milestone:

Discovery of bulk photovoltaic effect in semiconductors, 1955 Foundation of the physics of amorphous semiconductors.

Plaque citation summarizing the achievement and its significance:

In 1955, Jan Tauc discovered bulk photovoltaic effect in semiconductors and spin-orbit splitting in germanium during his work in this building. Later he gave foundation to the physics of amorphous semiconductors.

In what IEEE section(s) does it reside?

Czech chapter

IEEE Organizational Unit(s) which have agreed to sponsor the Milestone:

IEEE Organizational Unit(s) paying for milestone plaque(s):

Unit: Czechoslovakia Section
Senior Officer Name: Matěj Pácha

IEEE Organizational Unit(s) arranging the dedication ceremony:

Unit: Czechoslovakia Section
Senior Officer Name: Matěj Pácha

IEEE section(s) monitoring the plaque(s):

IEEE Section: Czechoslovakia Section
IEEE Section Chair name: Matěj Pácha

Milestone proposer(s):

Proposer name: Pavel Ripka
Proposer email: Proposer's email masked to public

Please note: your email address and contact information will be masked on the website for privacy reasons. Only IEEE History Center Staff will be able to view the email address.

Street address(es) and GPS coordinates of the intended milestone plaque site(s):

Cukrovarnicka 10, Praha 6, Czech Republic 50.0941683N / 14.3849436E

Describe briefly the intended site(s) of the milestone plaque(s). The intended site(s) must have a direct connection with the achievement (e.g. where developed, invented, tested, demonstrated, installed, or operated, etc.). A museum where a device or example of the technology is displayed, or the university where the inventor studied, are not, in themselves, sufficient connection for a milestone plaque.

Please give the address(es) of the plaque site(s) (GPS coordinates if you have them). Also please give the details of the mounting, i.e. on the outside of the building, in the ground floor entrance hall, on a plinth on the grounds, etc. If visitors to the plaque site will need to go through security, or make an appointment, please give the contact information visitors will need. Building of the Institute of Physics Czech Academy of Sciences, where Tauc worked for many years

Are the original buildings extant?


Details of the plaque mounting:

Outside the building on the wall facing public street

How is the site protected/secured, and in what ways is it accessible to the public?

The plaque will be accessible to the public and monitored by receptionist of the Institute.

Who is the present owner of the site(s)?

Still the same institute under slightly different name.

What is the historical significance of the work (its technological, scientific, or social importance)?

Jan Tauc Considerations on the application of semiconductors for energy conversion (solar or thermal energy into electricity and vice versa – electricity into thermal energy) are perhaps as old as the investigations of these materials themselves. The first boom of these efforts appeared at the turn of the forties and fifties of the 20th century. And just in that time Jan Tauc started his admirable search into the nature of the basic phenomena responsible for the wanted properties of this fascinating class of materials. He discovered the bulk photovoltaic effect and made a unified classification of the various types of electromotoric forces (EMF, photo and thermoelectric effects) in semiconductors. These studies aroused great response in the scientific community – the citations of [1] and [2] are appearing even in our days – in 2016 and 2015, respectively. No surprise that his book on EMF issued originally in 1958 in Czech was translated into several languages and published finally in English at Pergamon [3]. It represents an excellent updated (to the year 1962) summary of the topic. The same basic question – what physical processes are behind the interesting and promising properties of the materials – turned his interest to the studies of the band structure of semiconductors by optical methods, mainly reflectivity spectra. One of the main goals in this field was undoubtedly the discovery of the spin-orbit splitting in germanium by studying the reflectivity spectra of the Ge-Si alloys [4, 5]. The results of these studies were reviewed in a chapter of the prestigious series Progress in Semiconductors [6]. It should be emphasized that since that time optical methods are widespread in many academic and industrial laboratories and present nowadays one of the basic routine methods for testing the materials, not only for the basic investigations. The studies [4, 5] investigated the changes induced in the crystalline material when the short-range order (SRO) is disturbed (by the alloying effect), whereas the crystalline structure (long-range order - LRO) remains unaffected. The question what happens if the LRO is missing then appears quite natural. Like many other problems, also this issue has a long history, see, e.g. the review [7] from the beginning of the sixties. Nevertheless, it is the year 1965, which is taken for the onset of the “modern” history of the field of amorphous and liquid semiconductors. The thing is that in that year the first International Conference in Amorphous and Liquid Semiconductors took place. It was in Prague and Jan Tauc was the principal organizer. (It was a small, unpretentious event. Since that time this conference become a wide and large forum for the exchange of the ideas. It is organized every two years, now as Conference on Amorphous and Nano-crystalline Semiconductors (ICANS). Its 27th continuance took place in Korea in 2017.) According to the Nobel Lecture given by N.F. Mott in December 1977, there are three fathers “of this branch of science”, namely Boris T. Kolomiets (Leningrad), Radu Grigorovici (Bucharest) and Jan Tauc. A benchmark of this onset is undoubtedly also the joint Czech-Rumanian paper [8]. This is not only the most cited paper of the authors, but by a long shot the most cited paper ever published in physica status solidi (over 4000 citations and this number is permanently growing). Jan Tauc, as one of the leading persons often reviewed the progress of the field and also was appointed as an editor of the collection [9]. The number of amorphous and glassy semiconductors studied increased considerably over the years, nevertheless the interest in the basic “classical” semiconductors like germanium and especially silicon persists. Doped hydrogenated amorphous silicon (a-Si:H) was widely studied as a promising candidate for the production of the solar cells. No surprise that Jan Tauc again persuaded basic research in the fundamental problems connected with this material (e.g. [10,11]). Indeed, these investigations took place already out of Czechoslovakia. Jan Tauc started his professional career as electrical engineer. A deep concern to get into the essence of the phenomena lead him to the investigations of the basic mechanisms responsible for the behavior of the electronic devices. And results of these investigations have helped in developing new materials and devices.

What obstacles (technical, political, geographic) needed to be overcome?

After the 1948 communist coup in Czechoslovakia, Tauc was not permitted to travel abroad, after he received one-year fellowship from the British Council to work with Professor Mott in Bristol in theoretical solid-state physics. He refused to join communist party and thus he remained on the blacklist till 1956. After Soviet Union occupied Czechoslovakia in 1968, Tauc left the country for United States.

What features set this work apart from similar achievements?

Supporting texts and citations to establish the dates, location, and importance of the achievement: Minimum of five (5), but as many as needed to support the milestone, such as patents, contemporary newspaper articles, journal articles, or chapters in scholarly books. 'Scholarly' is defined as peer-reviewed, with references, and published. You must supply the texts or excerpts themselves, not just the references. At least one of the references must be from a scholarly book or journal article. All supporting materials must be in English, or accompanied by an English translation.

[1] 1957 The generation of an EMF in semiconductors with nonequilibrium current carrier concentrations. Rev. Mod. Phys. 29:308-324. {72 citations} [2] 1959 Electron impact ionization in semiconductors. J. Phys. Chem. Solids 8:219-223. {78 citations} [3] Jan Tauc (1962). Photo and thermoelectric effects in semiconductors. Pergamon Press. [4] 1960 With E. Antoncik. Optical observation of spin-orbit interaction in germanium. Phys. Rev. Lett. 5:253-254. {32 citations} [5] 1961 With A. Abrahám, Optical investigation of the band structure of Ge-Si alloys. J. Phys. Chem. Solids 20:190-192. {69 citations, the last one in 2011} [6] 1965 Optical properties of semiconductors in the visible and ultra-violet range. Progress in Semiconductors 9:87-133. Heywood, London. [7] 1960 A.F. Ioffe, A.R. Regel, Non-crystalline, Amorphous, and Liquid Electronic Semiconductors. Progress in Semiconductors 4:237-x. Heywood, London. [8] 1966 With R. Grigorovici and A. Vancu. Optical properties and electronic structure of amorphous germanium. Phys. Stat. Solidi B 15:627. (4033 citations in WoS ) [9] Jan Tauc (1974). Amorphous and liquid semiconductors. Plenum. ISBN 978-0-306-30777-5. [10] 1981 with Z. Vardeny. Hot-carrier thermalization in amorphous silicon. Phys. Rev. Lett. 46:1223-1226. {66 citations} [11] 1982 with Z. Vardeny, D. Pfost et al. Picosecond photoinduced transmission associated with deep traps in phosphorus-doped a-Si:H. Phys. Rev. Lett. 48:1132-1135. {66 citations}

Supporting materials (supported formats: GIF, JPEG, PNG, PDF, DOC): All supporting materials must be in English, or if not in English, accompanied by an English translation. You must supply the texts or excerpts themselves, not just the references. For documents that are copyright-encumbered, or which you do not have rights to post, email the documents themselves to Please see the Milestone Program Guidelines for more information.

Manuel Cardona, Sidney Nagel, Richard Zallen, and Karel Závěta (2011) Jan Tauc. National Academy of Sciences, Washington

Manuel Cardona; Sidney Nagel; Richard Zallen; Karel Závěta (2011). "Jan Tauc". Physics Today. 64 (7): 64. Bibcode:2011PhT....64g..64C. doi:10.1063/PT.3.1177.

Please email a jpeg or PDF a letter in English, or with English translation, from the site owner(s) giving permission to place IEEE milestone plaque on the property, and a letter (or forwarded email) from the appropriate Section Chair supporting the Milestone application to with the subject line "Attention: Milestone Administrator." Note that there are multiple texts of the letter depending on whether an IEEE organizational unit other than the section will be paying for the plaque(s).