Possible excited states in Si:Se and Si:Te prepared by femtosecond-laser irradiation of Si coated with Se or Te film
Abstract
Se- and Te-doped silicon were prepared by irradiation of Si in the presence of Se and Te thin films, and then appropriate n+-n photodiodes were fabricated from the two materials. With I-V characteristics measurements, it is found that the Te doped diode exhibits smaller dark current and greater photocurrent compared with Se- doped diode. With Fourier-transform photoconductivity spectroscopy measurements, sub-bandgap photocurrent features are observed for Se- and Te-doped diodes. The optical activation energies for Si:Se are in good agreement with the known Se levels Sec0(X1) (116 meV) and Se2+ (390 meV). The optical activation energies for Si:Te are in good agreement with the known Te levels Te+ (411 meV), Tec0 (X1) (92 meV), Tec+ (X1) (364 meV) and Tec+ (X2) (173 meV). The observed dopant centers in silicon facilitate the application of Si:Se and Si:Te in the sub-bandgap photoelectric devices.
- Publication:
-
Infrared Physics and Technology
- Pub Date:
- January 2020
- DOI:
- 10.1016/j.infrared.2019.103150
- Bibcode:
- 2020InPhT.10403150D
- Keywords:
-
- Silicon;
- Femtosecond laser pulse;
- Se doped;
- Te doped;
- Activation energy