Effect of annealing temperature on thermo‐diffusional boron doping of silicon nanowire arrays probed by Raman spectroscopy

• Published in: Journal of Raman spectroscopy 2020-11, Vol.51 (11), p.2146-2152
• Main Authors: Efimova, A. I., Lipkova, E. A., Gonchar, K. A., Presnov, D. E., Eliseev, A. A., Pavlikov, A. V., Timoshenko, V. Yu
• Format: Article
• Language: English
• Subjects: Annealing; Arrays; Boron; boron doping; Chemical etching; Current carriers; Doping; Electrical properties; Etching; Fano resonance; free charge carriers; Nanotechnology; Nanowires; Optoelectronics; Raman spectra; Raman spectroscopy; Silicon; silicon nanowires; Silicon wafers; Spectroscopy; Spectrum analysis
• ISSN: 0377-0486; 1097-4555
• DOI: 10.1002/jrs.5956

Arrays of silicon nanowires (SiNWs) with characteristic transverse nanowire size of the order of 100 nm were fabricated by metal‐assisted chemical etching of monocrystalline silicon wafers followed by thermo‐diffusional doping with boron and studied by means of Raman spectroscopy considering the Fano effect related to the free charge carriers (holes) in SiNWs. The hole concentration of the order of 1020 cm−3 was shown to be achieved for SiNWs annealed at 950–1000°C and the peak intensity of Raman scattering of SiNWs dropped exponentially with the increasing free‐hole concentration. The obtained results can be used for the express diagnostics of the electrical properties of silicon nanostructures for applications in optoelectronics, sensorics, and thermoelectric devices. Raman spectra of silicon nanowire arrays, which are grown by metal‐assisted chemical etching followed with thermo‐diffusional boron doping at different annealing temperatures, are probed by means of the Raman spectroscopy, considering both the Fano resonance modified spectra and Raman scattering intensity. The obtained results are useful for express‐diagnostics of free charge carriers (FCCs) in doped silicon nanostructures.