New insights into the temperature-dependent photoluminescence of Mg-doped GaAs nanowires and epilayers

Falcão, Bruno P.; Leitao, J. P.; Correia, M. R.; Leitao, Miguel F.; Soares, M.R.; Moreira, M. V. B.; Oliveira, A. G. de; Matinaga, F. M.; González, J. C.

doi:10.1039/c4tc01050g

Cited by 14 publications

(16 citation statements)

References 52 publications

(69 reference statements)

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“…Concerning the redshift, it cannot be ascribed to a temperature effect on the band-gap energy because the observed shift is much higher than the one observed experimentally by Sarswat and Free [81]. Actually, in that work, the data showed almost no change of the band gap energy in the range ∼7-100 K which is compatible with a high doping level as expected for the semiconductor [82]. The experimental behavior in the investigated temperature range (∼7-280 K), is different from previous reports in the scope of BI transitions [34,68,69].…”

Section: Discussion Of the Resultsmentioning

confidence: 40%

Radiative transitions in highly doped and compensated chalcopyrites and kesterites: The case ofCu2ZnSnS4

Teixeira

Sousa

et al. 2014

Phys. Rev. B

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The theoretical models of radiative recombinations in both CuIn 1−x Ga x Se 2 chalcopyrite and Cu 2 ZnSnS 4 kesterite, and related compounds, were revised. For heavily doped materials, electrons are free or bound to large donor agglomerates which hinders the involvement of single donors in the radiative recombination channels. In this work, we investigated the temperature and excitation power dependencies of the photoluminescence of Cu 2 ZnSnS 4 -based solar cells in which the absorber layer was grown through sulphurization of multiperiod structures of precursor layers. For both samples the luminescence is dominated by an asymmetric band with peak energy at ∼1.22 eV, which is influenced by fluctuating potentials in both conduction and valence bands. A value of ∼60 meV was estimated for the root-mean-square depth of the tails in the conduction band. The radiative transitions involve the recombination of electrons captured by localized states in tails of the conduction band with holes localized in neighboring acceptors that follow the fluctuations in the valence band. The same acceptor level with an ionization energy of ∼280 meV was identified in both absorber layers. The influence of fluctuating potentials in the electrical performance of the solar cells was discussed.

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Section: Discussion Of the Resultsmentioning

confidence: 40%

Radiative transitions in highly doped and compensated chalcopyrites and kesterites: The case ofCu2ZnSnS4

Teixeira

Sousa

et al. 2014

Phys. Rev. B

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“…Before the presentation of the results, we will mention briefly the common temperature dependence of the bandgap in a semiconductor. As the temperature increases, the thermal expansion coefficient of the lattice and the electron–phonon interaction promote the broadening and the redshift of the energy levels, which leads to a reduction of the bandgap [46,62–63]. Among the several theoretical models available in the literature, one that probably better describes the temperature dependence of the bandgap in the whole temperature range for several semiconductors, namely for the ZB crystalline phase of GaAs, was proposed by Pässler [63]:…”

Section: Resultsmentioning

confidence: 99%

“…This behavior suggests the involvement of a relatively deep radiative state in a particular crystalline phase. Thus, the bandgap shrinkage induced by the increase of temperature will be more effective for high temperatures [46]. A higher localization of charge carriers in such a state is compatible with a value of m lower than 1 and non-radiative de-excitation channels involving discrete energy levels if a high density of non-radiative defects is assumed on that sample.…”

Section: Discussionmentioning

confidence: 99%

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Substrate and Mg doping effects in GaAs nanowires

Kannappan¹,

Sédrine²,

Teixeira³

et al. 2017

Beilstein J. Nanotechnol.

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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 × 1016 cm−3 to 1.4 × 1017 cm−3. The estimated electrical mobility was in the range ≈0.3–39 cm2 /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.

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“…Mg presents the additional advantage of p‐doping all III–V compounds, including nitrides semiconductors, simplifying the integration of diverse III–V materials. We have recently demonstrated the feasibility of growing Mg‐doped GaAs NWs and studied their optical properties . In this work, we study the electronic transport in Mg‐doped GaAs NWs.…”

Section: Introductionmentioning

confidence: 99%

Electronic transport in p‐type Mg‐doped GaAs nanowires

Cifuentes

Limborço

Viana

et al. 2016

Physica Status Solidi (b)

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The electronic transport properties of several Mg-doped GaAs nanowires are investigated. It is shown that Mg can be successfully used as a nontoxic and noncarcinogenic p-type dopant in GaAs nanowires. The doping levels, expanding over two orders of magnitude, and free holes mobility in the NW were obtained by the analysis of field effect transistors transfer curves. The study of the temperature dependence of the electrical resistivity of the nanowires shows that electronic transport changes from conduction of free holes, above room temperature, to variable hopping conduction at lower temperatures. Both, Mott and Efros-Shklovskii variable range hopping mechanism were clearly identified in the nanowires.

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New insights into the temperature-dependent photoluminescence of Mg-doped GaAs nanowires and epilayers

Cited by 14 publications

References 52 publications

Radiative transitions in highly doped and compensated chalcopyrites and kesterites: The case ofCu2ZnSnS4

Radiative transitions in highly doped and compensated chalcopyrites and kesterites: The case ofCu2ZnSnS4

Substrate and Mg doping effects in GaAs nanowires

Electronic transport in p‐type Mg‐doped GaAs nanowires

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