#university of illinois

Search for new semiconductors heats up with gallium oxide

University of Illinois electrical engineers have cleared another hurdle in high-power semiconductor fabrication by adding the field’s hottest material – beta-gallium oxide – to their arsenal. Beta-gallium oxide is readily available and promises to convert power faster and more efficiently than today’s leading semiconductor materials – gallium nitride and silicon, the researchers said.

Their findings are published in the journal ACS Nano.

Flat transistors have become about as small as is physically possible, but researchers addressed this problem by going vertical. With a technique called metal-assisted chemical etching – or MacEtch – U. of I. engineers used a chemical solution to etch semiconductor into 3D fin structures. The fins increase the surface area on a chip, allowing for more transistors or current, and can therefore handle more power while keeping the chip’s footprint the same size.

Developed at the U. of I., the MacEtch method is superior to traditional “dry” etching techniques because it is far less damaging to delicate semiconductor surfaces, such as beta-gallium oxide, researchers said.

“Gallium oxide has a wider energy gap in which electrons can move freely,” said the study’s lead author Xiuling Li, a professor of electrical and computer engineering. “This energy gap needs to be large for electronics with higher voltages and even low-voltage ones with fast switching frequencies, so we are very interested in this type of material for use in modern devices. However, it has a more complex crystal structure than pure silicon, making it difficult to control during the etching process.”

Read more.

Today’s post comes from Violet Fox, who previously wrote ourpost about Henriette Avram. Violet is on Twitter at@violetbfox.

Margaret Mann (1873-1960) was a librarian and educator whose work and scholarship emphasized the role of theory in cataloging and classification. Her passion for information organization inspired the many students she taught to see cataloging and classification as an essential service to library users.

Born in Cedar Rapids, Iowa on April 9, 1873, as an adolescent Mann moved with her family to Chicago and graduated from Englewood High School. She enrolled at Chicago’s Armour Institute in 1893, as one of the first twelve students in the library program (the Armour Institute was only the fourth school for the education of librarians in the U.S. and the first west of the Alleghanies). There she studied preservation, cataloging, accessioning, and shelf-listing, as well as learning library hand. After graduating a year later, most of her cohort moved on to library jobs, but Mann was asked to stay on as an assistant at Armour, serving as a cataloger and occasional instructor. When the library science department was moved from Armour to the University of Illinois in 1897, Mann was appointed to the staff of the new program. While teaching at the University of Illinois, she also worked towards creating consistent policies of cataloging and classification within its library. Mann moved on to the Carnegie Library in Pittsburgh in 1902, serving as head of the Cataloging Department until 1919. From 1919 to 1924 she undertook a massive reorganization of the collections of the Library of the Engineering Societies in New York City.

After returning from teaching cataloging and classification at the École de Bibliothécaires in Paris in 1926, she began as an instructor at the University of Michigan as one of the first three faculty hired at the beginning of the school’s library science program. Unlike her own library school experience thirty years earlier, which was highly focused on everyday library practice, Mann’s publications and teaching focused on the need to understand the theory of cataloging and classification to serve library users well. Her textbook, “An Introduction to Cataloging and the Classification of Books,” first published in 1930 by ALA, was widely used by library schools and helped standardize the cataloging content taught to library students. She would remain at the University of Michigan until her retirement at age 65 in 1938, impressing upon her many students the important role of information organization in libraries.

Mann died in 1960 but her name and legend live on in the University of Michigan’s Margaret Mann Award, established in 1938, as well as in the Margaret Mann Citation, awarded yearly by ALA to recognize outstanding professional achievement in cataloging or classification. Mann was also listed within American Libraries’s 1999 article on “100 of the Most Important Leaders We Had in the 20th Century”.

Resources consulted:

Clack, Doris H. (1993). Education for Cataloging.Cataloging & Classification Quarterly, 16:3, 27-37, DOI: 10.1300/J104v16n03_04

Grotzinger, Laurel. (1970). Margaret Mann: The Preparatory Years.Journal of Education for Librarianship, 10:4, 302-315, DOI: 10.2307/40322089
University of Michigan Faculty History Project

Wikipedia biography of Margaret Mann