First principle study of V-implantation in highly-doped silicon materials

• Gregorio García^a, b, , , 
• Marcos Casanova-Páez^c, 
• Pablo Palacios^a, d, 
• Eduardo Menéndez-Proupin^c,
• Perla Wahnón^a, b

• ^a Instituto de Energía Solar, ETSI Telecomunicación, Universidad Politécnica de Madrid, 28040 Madrid, Spain
• ^b Departamento de Tecnología Fotónica y Bioingeniería, ETSI Telecomunicación, Universidad Politécnica de Madrid, Ciudad Universitaria, s/n, 28040 Madrid, Spain
• ^c Departamento de Física, Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, 780-0003 Ñuñoa, Santiago, Chile
• ^d Departamento de Física aplicada a las Ingenierías Aeronáutica y Naval, ETSI Aeronáutica y del Espacio, Pz. Cardenal Cisneros, 3, 28040 Madrid, Spain

Received 4 April 2017, Accepted 2 May 2017, Available online 29 May 2017

Abstract

Density Functional Theory (DFT) has been used to study structural and electronic properties of new compounds based on V-implanted Si and their potential as infrared photodetectors. Effects derived from the implantation of V on bulk-Si are calculated at different configurations, i.e., substitutional (V_Si) and interstitial (V_i) positions as well as the effect of Si vacancies. Despite all implantation processes are energetically penalized, V_i-implanted compound leads to the lowest formation energies. Furthermore, interstitial implantation in the vicinity of a Si vacancy would lead to a highly favored process. The analysis of the electronic structure shows that V_i-implanted compounds own an intermediate band (due to t_2g states of vanadium atom), which allows new electronic transitions below 1.0 eV. To deal with the bandgap underestimation of common DFT methods, quasiparticle calculations have been applied via the G₀W₀ approximation. Applied correction to the bandgap based on GW has considerably improved theoretical results compared to experimental ones. The investigation of the absorption features points out that the absorption response can be extended up to infrared region via sub-gap transitions across the intermediate band. This work highlights the potential of V-implanted silicon based materials with infrared response.

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