High hole mobility and non-localized states in amorphous germaniumShow others and affiliations
2023 (English)In: APL Materials, E-ISSN 2166-532X, Vol. 11, no 4, p. 041115-, article id 041115Article in journal (Refereed) Published
Abstract [en]
Covalent amorphous semiconductors, such as amorphous silicon (a-Si) and germanium (a-Ge), are commonly believed to have localized electronic states at the top of the valence band and the bottom of the conduction band. Electrical conductivity is thought to occur through the hopping mechanism via these localized states. The carrier mobility of these materials is usually very low, in the order of similar to 10(-3)-10(-2) cm(2)/Vs at room temperature. In this study, we show that pure high-density amorphous Ge has exceptionally high carrier mobility, in the order of similar to 100 cm(2)/Vs, and a high hole concentration of similar to 10(18) cm(-3). The temperature-dependent conductivity of the material is also very-well defined with two distinctive regions, extrinsic and intrinsic conductivity, as in crystalline Ge. These results provide direct evidence for a largely preserved band structure and non-localized states within the valence band in high-density amorphous Ge, as previously suggested by Tauc et al. from optical characterization alone.
Place, publisher, year, edition, pages
AIP Publishing , 2023. Vol. 11, no 4, p. 041115-, article id 041115
National Category
Condensed Matter Physics
Identifiers
URN: urn:nbn:se:kth:diva-326654DOI: 10.1063/5.0146424ISI: 000967579800001Scopus ID: 2-s2.0-85158147031OAI: oai:DiVA.org:kth-326654DiVA, id: diva2:1755441
Note
QC 20230508
2023-05-082023-05-082023-06-08Bibliographically approved