Substrate and Mg doping effects in GaAs nanowires.

Autor: Kannappan P; Departamento de Física & I3N, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.; Crystal Growth Centre, Anna University, Chennai 600 025, India.; Present address: Department of Physics, Bannari Amman Institute of Technology, Sathyamangalam 638 401, India., Sedrine NB; Departamento de Física & I3N, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal., Teixeira JP; Departamento de Física & I3N, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal., Soares MR; Laboratório Central de Análises, Universidade de Aveiro, 3810-193 Aveiro, Portugal., Falcão BP; Departamento de Física & I3N, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal., Correia MR; Departamento de Física & I3N, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal., Cifuentes N; Departamento de Física, Universidade Federal de Minas Gerais, 30123-970 Belo Horizonte, Minas Gerais, Brazil., Viana ER; Departamento Acadêmico de Física-DAVIS, Universidade Tecnológica Federal do Paraná-UTFPR, Av. Sete de Setembro, 3165-Rebouças, ZIP 80230-901, Curitiba, PR, Brazil., Moreira MVB; Departamento de Física, Universidade Federal de Minas Gerais, 30123-970 Belo Horizonte, Minas Gerais, Brazil., Ribeiro GM; Departamento de Física, Universidade Federal de Minas Gerais, 30123-970 Belo Horizonte, Minas Gerais, Brazil., de Oliveira AG; Departamento de Física, Universidade Federal de Minas Gerais, 30123-970 Belo Horizonte, Minas Gerais, Brazil., González JC; Departamento de Física, Universidade Federal de Minas Gerais, 30123-970 Belo Horizonte, Minas Gerais, Brazil., Leitão JP; Departamento de Física & I3N, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
Jazyk: angličtina
Zdroj: Beilstein journal of nanotechnology [Beilstein J Nanotechnol] 2017 Oct 11; Vol. 8, pp. 2126-2138. Date of Electronic Publication: 2017 Oct 11 (Print Publication: 2017).
DOI: 10.3762/bjnano.8.212
Abstrakt: Mg doping of GaAs nanowires has been established as a viable alternative to Be doping in order to achieve p-type electrical conductivity. Although reports on the optical properties are available, few reports exist about the physical properties of intermediate-to-high Mg doping in GaAs nanowires grown by molecular beam epitaxy (MBE) on GaAs(111)B and Si(111) substrates. In this work, we address this topic and present further understanding on the fundamental aspects. As the Mg doping was increased, structural and optical investigations revealed: i) a lower influence of the polytypic nature of the GaAs nanowires on their electronic structure; ii) a considerable reduction of the density of vertical nanowires, which is almost null for growth on Si(111); iii) the occurrence of a higher WZ phase fraction, in particular for growth on Si(111); iv) an increase of the activation energy to release the less bound carrier in the radiative state from nanowires grown on GaAs(111)B; and v) a higher influence of defects on the activation of nonradiative de-excitation channels in the case of nanowires only grown on Si(111). Back-gate field effect transistors were fabricated with individual nanowires and the p-type electrical conductivity was measured with free hole concentration ranging from 2.7 × 10 16 cm -3 to 1.4 × 10 17 cm -3 . The estimated electrical mobility was in the range ≈0.3-39 cm 2 / Vs and the dominant scattering mechanism is ascribed to the WZ/ZB interfaces. Electrical and optical measurements showed a lower influence of the polytypic structure of the nanowires on their electronic structure. The involvement of Mg in one of the radiative transitions observed for growth on the Si(111) substrate is suggested.
Databáze: MEDLINE
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