Enhanced Photoluminescence of Hydrogenated Amorphous Silicon Carbide Thin Films by Means of a Fast Thermal Annealing Process

Israel Vivaldo; Roberto C Ambrosio; Roberto López; Javier Flores-Méndez; Luis A Sánchez-Gaspariano; Mario Moreno; Filiberto Candia

doi:10.3390/ma13112643

Enhanced Photoluminescence of Hydrogenated Amorphous Silicon Carbide Thin Films by Means of a Fast Thermal Annealing Process

Materials (Basel). 2020 Jun 10;13(11):2643. doi: 10.3390/ma13112643.

Authors

Israel Vivaldo¹, Roberto C Ambrosio¹, Roberto López², Javier Flores-Méndez^{1

3}, Luis A Sánchez-Gaspariano¹, Mario Moreno⁴, Filiberto Candia¹

Affiliations

¹ Electronics Department, Benemérita Universidad Autónoma de Puebla, Puebla 72590, Mexico.
² Mechatronics Department, Tecnológico de Estudios Superiores de Jocotitlán, Carretera Toluca-Atlacomulco km 44.8, Ejido de San Juan y San Agustin, Jocotitlán 50700, Mexico.
³ Tecnológico Nacional de México/I.T. Puebla-División de Estudios de Posgrado e Investigación, Av. Tecnológico No. 420, Maravillas, Puebla 72220, Mexico.
⁴ Electronics Department, Instituto Nacional de Astrofísica, Óptica y Electrónica, Puebla 72000, Mexico.

Abstract

In this paper, the photoluminescence (PL) of hydrogenated amorphous silicon carbide (a-Si_1-xC_x:H) thin films obtained by Plasma Enhancement Chemical Vapor Deposition (PECVD) is reported. Strong PL is obtained after a fast annealing process for 60 s at temperatures of 200, 400, 600, and 800 °C. The thin films are characterized using Fourier Transform Infrared spectroscopy (FTIR), PL spectroscopy, and Energy-Dispersive X-ray Spectroscopy (EDS). According to the results of the structural characterization, it is deduced that a structural rearrangement of the amorphous matrix is carried out during the fast annealing process, which results in different degrees of oxidation on the a-Si_1-xC_x:H films. The PL peak position shifts towards higher energies as the temperature increases. The sample deposited with a silane/methane flux ratio of 37.5 at an Radio Frequency (RF) power of 6 W experiences an increase in PL intensity of more than nine times, with a displacement in the peak position from 2.5 eV to 2.87 eV, at 800 °C. From the PL analysis, we observe two emission bands: one centered in the near infrared and other in the visible range (with a blue peak). This study opens the possibility to use such thin films in the development of optoelectronics devices, with potential for application in solar cells.

Keywords: amorphous silicon carbide; fast thermal annealing process; photoluminescence; plasma enhancement chemical vapor deposition.