SPE grown BaSi₂ on Si(111) substrates: optical and photoelectric properties of films and diode heterostructures on their base

The study of the optical properties of BaSi2 films grown on n-type silicon by solid-phase epitaxy showed that the band gap of BaSi2 is about 1.20 eV. Formed Al/BaSi2/Si mesa-diodes showed the presence of two maxima in the photoresponse spectra at 1.15-1.20 eV and 1.5-1.6 eV at 300 K and spectra expansion to 0.7 eV at 80 K. Analysis of the I-V characteristics and photoresponse spectra at two biases showed that a BaSi2-n/Si-n isotype heterojunction is formed with a double barrier layer, quasi-linear I-V characteristics, and contribution of defect states to the photoresponse at 80 K. Band diagrams of the BaSi2-n/Si-n heterojunction with surface states at zero, forward and reverse biases were constructed, which made it possible to explain features in the photoresponse spectra at energies of 1.0-2.1 eV and the first detected IR photoresponse at 0.7-1.0 eV based on charging and photogeneration of defect states at 80 K. (c) 2020 The Japan Society of Applied Physics