2010/11/05 by N. Sircar, N. R. Sircar, S. Ahlers +4 · 9 citations
Chemistry · Engineering · Physics and Astronomy · #Chemistry #Composite material #Condensed matter physics #Conductivity #Electrical conduction #Electrical engineering #Electrical resistivity and conductivity #Epitaxy #Hall effect #Layer (electronics) #Materials science #Nanotechnology #Optoelectronics #Photonic and Optical Devices #Physics #Quantum and electron transport phenomena #Semiconductor Quantum Structures and Devices #Substrate (aquarium) #Thermal conduction #Thin film #cond-mat.mtrl-sci #cond-mat.other
paper · pdf · doi:10.1103/physrevb.83.125306
published in Physical Review B 83(12) (American Physical Society) · 9 pages, 9 figures
arxiv created 2010/11/05 · openalex publication_date 2011/03/18 · arxiv updated 2011/03/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present evidence that electrical transport studies of epitaxial p-type GeMn thin films fabricated on high-resistivity Ge substrates are severely influenced by parallel conduction through the substrate, related to the large intrinsic conductivity of Ge due to its small band gap. Anomalous Hall measurements and large magnetoresistance effects are completely understood by taking a dominating substrate contribution as well as the measurement geometry into account. It is shown that substrate conduction persists also for well-conducting, degenerate, p-type thin films, giving rise to an effective two-layer conduction scheme. Using n-type Ge substrates, parallel conduction through the substrate can be reduced for the p-type epilayers, as a consequence of the emerging pn-interface junction. GeMn thin films fabricated on these substrates exhibit a negligible magnetoresistance effect. Our study underlines the importance of a thorough characterization and understanding of possible substrate contributions for electrical transport studies of GeMn thin films.