On the Ge shallow-to-deep level transition in Al-rich AlGaN
Abstract
Contrary to the arsenides where donors undergo stable DX transition, we find that Ge in AlGaN does not suffer from the DX transition; instead, it undergoes a shallow donor (30 meV) to deep donor (150 meV) transition at ∼50% Al content in the alloy. This finding is of profound technological importance as it removes fundamental doping limitations in AlGaN and AlN imposed by the presumed DX−1 acceptor state. The charge state of Ge below and above the transition was determined by co-doping with Si, which remains a shallow donor in AlGaN for up to 80% Al. It was found that Ge occupied a donor state with a (0/+) thermodynamic transition for AlGaN alloys below and above the transition. Ge as a shallow donor was completely ionized at room temperature; however, the ionization of the deep donor required elevated temperatures, commensurate with its higher ionization energy. This behavior is not unique to Ge; preliminary findings show that Si and O in AlGaN may behave similarly.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 03, 2021
- Source ID
- 10.1063/5.0059037
Entities
People
- Andrew Klump
- Dennis Szymanski
- Dolar Khachariya
- Ji Hyun Kim
- Pegah Bagheri
- Pramod Reddy
- Ramón Collazo
- Ronny Kirste
- Seiji Mita
- Spyridon Pavlidis
- Yan Guan
- Zlatko Sitar
Organizations
- Air Force Office of Scientific Research
- Army Research Office
- National Science Foundation
- North Carolina State University