OLMOS ASAR JIMENA ANAHÍ
Congresos y reuniones científicas
Título:
Novel III-Te-graphene van der Waals heterojunctions for optoelectronic devices
Autor/es:
JIMENA A. OLMOS ASAR; CEDRIC ROCHA LEÃO; ADALBERTO FAZZIO
Lugar:
Belo Horizonte
Reunión:
Conferencia; 18th International Conference on the Science and Application of Nanotubes and Low-dimensional Materials; 2017
Resumen:
Gallium telluride, with a moderate direct band gap, presents an intense excitonic absorption and fast response time 1 , which makes it interesting for applications in optoelectronic devices, such as solar panels and radiation detectors. These applications, however, have been hindered due to the low mobility of charge carriers and short lifetime of photoexcitations in this material. In this work we propose that these limitations could be overcome by van der Waals heterostructures of GaTe monolayers and graphene sheets, combining the high photoabsorption
of the former with the ballistic transport of the latter 2 . Our analysis indicate that such structures have a strong binding energy and that the band offset is such that transfer of photoexcited electrons from GaTe to graphene should be spontaneous. However, the band edges of GaTe in the brillouin zone with respect to the dirac cone in graphene would need the involvement of phonons to mediate the transfer across the van der Waals
heterostructure. We propose also two new hypothetical 2D materials: InTe and TlTe monolayers with the same atomic arrangement as GaTe. Thermodynamic and dynamical analysis indicate that these structures, which should also present high photoresponsivity, are stable. The combination of these materials with graphene shows strong binding as well. Specifically for the case of TlTe we find that the band edges coincide with graphene?s dirac cone in the brillouin zone, resulting in optimal transfer of photoexcited carriers 3 .
1 F. Liu et al., ACS Nano 8, 752 (2014)
2 N. K. S et al., Nature 490, 192 (2012)
3 J. A. Olmos-Asar et al., submitted (2017)
of the former with the ballistic transport of the latter 2 . Our analysis indicate that such structures have a strong binding energy and that the band offset is such that transfer of photoexcited electrons from GaTe to graphene should be spontaneous. However, the band edges of GaTe in the brillouin zone with respect to the dirac cone in graphene would need the involvement of phonons to mediate the transfer across the van der Waals
heterostructure. We propose also two new hypothetical 2D materials: InTe and TlTe monolayers with the same atomic arrangement as GaTe. Thermodynamic and dynamical analysis indicate that these structures, which should also present high photoresponsivity, are stable. The combination of these materials with graphene shows strong binding as well. Specifically for the case of TlTe we find that the band edges coincide with graphene?s dirac cone in the brillouin zone, resulting in optimal transfer of photoexcited carriers 3 .
1 F. Liu et al., ACS Nano 8, 752 (2014)
2 N. K. S et al., Nature 490, 192 (2012)
3 J. A. Olmos-Asar et al., submitted (2017)
