Germanium (Ge) is the most compatible semiconductor material with silicon-based complementary metal-oxide semiconductor technology, which has higher electron and hole mobility than Si, leading to enhanced device performance. In addition, semiconductor nanowires (NWs) have attracted significant attention as promising candidates for next-generation nanoscale devices. Due to their unique geometry and physical properties, NWs show excellent optical and electrical properties such as quantum size effects, enhanced light absorption, and high biological and chemical sensitivity. Furthermore, high response to light irradiation is one of the most significant properties of semiconductor NWs, which makes them excellent candidates for photodetectors. Hence, Ge NWs are promising high-mobility nanostructures for optoelectronic devices.
Despite constant improvement in the performance of single NW-based devices, determining their electrical properties remains challenging. Here, a symmetric six-contact Hall bar configuration is developed for top-down fabricated highly doped Ge NWs with different widths down to 30 nm, which simultaneously facilitates Hall effect and four-probe resistance measurements. Furthermore, accurate control of doping and fabrication of metal contacts on n-type doped Ge NWs with low resistance and linear characteristics remain significant challenges in Ge-based devices. Therefore, a combined approach is reported to fabricate Ohmic contacts on n-type doped Ge NWs using ion implantation and rear-side flash lamp annealing. This approach allows the fabrication of axial p–n junctions along the single NWs with different widths. The fabricated devices demonstrated rectifying characteristics in dark conditions. The photoresponse of the axial p–n junction photodetectors was investigated under three different illumination wavelengths of 637 nm, 785 nm, and 1550 nm. Moreover, the fabricated axial p–n junction photodetector demonstrated a high-frequency response up to 1 MHz at zero bias.
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:86557 |
| Date | 25 July 2023 |
| Creators | Echresh, Ahmad |
| Contributors | Georgiev, Yordan M., Rebohle, Lars, Helm, Manfred, Erbe, Artur, Technische Universität Dresden, Helmholz-Zentrum Dresden-Rossendorf |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, doc-type:doctoralThesis, info:eu-repo/semantics/doctoralThesis, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
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