Electrical transport properties of Ge-doped GaN nanowires. (11th March 2015)

• Record Type: Journal Article
• Authors: Schäfer, M; Günther, M; Länger, C; Müßener, J; Feneberg, M; Uredat, P; Elm, M T; Hille, P; Schörmann, J; Teubert, J; Henning, T; Klar, P J; Eickhoff, M
• Is Part Of: Nanotechnology. Volume 26:Number 13(2015)
• Publication Date: 2015-03-11
• Subjects: GaN nanowires -- electrical transport properties -- Seebeck coefficient -- micro photoluminescence -- charge carrier concentration -- gallium nitride -- molecular beam epitaxy; Nanotechnology -- Periodicals; Nanotechnology -- Periodicals; Nanotechnology; Publications périodiques; Nanotechnologies; Periodicals; 620.5
• DOI: 10.1088/0957-4484/26/13/135704
• Languages: English
• ISSNs: 0957-4484

Abstract

Abstract: The conductivity and charge carrier concentration of single GaN nanowires (NWs) doped with different concentrations of Ge were determined by four-point resistivity and temperature-dependent Seebeck coefficient measurements. We observed high carrier concentrations ranging from 9.1 × 10 18 to 5.5 × 10 19 cm −3, well above the Mott density of 1.6 × 10 18 cm −3, and conductivities up to 625 S cm −1 almost independent of the NW diameter. The weak temperature dependence of the conductivity between 2 and 10 K could be assigned to the formation of an impurity band. For the sample with the highest conductivity metallic behaviour was found, indicated by a positive temperature coefficient of the resistivity. The near band edge emission analyzed by micro-photoluminescence spectroscopy showed only a small increase of the peak width up to 70 meV and no spectral shift for carrier concentrations up to 5.5 × 10 19 cm −3 . The latter was attributed to the simultaneous influence of band filling, band gap renormalization, and strain.