Optical and electrical characterization of β-FeSi2 epitaxial thin films on silicon substrates

Abstract

Electrical measurements have been carried out on epitaxial FeSi2 layers on silicon substrates, the silicide thickness being either 180 or 350 Å. A direct gap of 0.85 eV was measured by optical absorption. Current-voltage characteristics of mesa-structures Cr/Fe/FeSi2/Si show a p-type semiconductor behavior. Capacitance-voltage and capacitance-temperature data at different frequencies indicate a large response of deep levels or interface states. Admittance spectroscopy yields the activation energy and capture cross section of two levels. Finally an energy-band diagram is proposed.

Electrochemical Formation of Ca-Si in Molten CaCl2-KCl

“…In addition, the bandgap energy of metal silicides can be extended from the infrared to the visible region by appropriate choice of metal elements and phases of the compounds. [2][3][4][5] Among the numerous metal silicides reported, Ca-Si metal silicides are well known semiconductor materials that exhibit superconductive properties. For example, Ca 2 Si is a semiconductor with an energy gap of 1.9 eV, 6 while CaSi is expected to show high hydrogen storage capacity.…”

Synthesis and characterization of β-phase iron silicide nano-particles by chemical reduction

“…On the other hand Filonov et al [1] shows the experimental direct band gap of 0.87 eV which is in good agreement with theoretically calculated value of direct band gap of 0.825 eV at Y point. Lefki et al [36] and Yang et al [49] both have obtained a direct band gap of 0.85 eV from the experimental analysis which agrees quite well to that (0.84 eV) observed by Wang et al [3]. Birdwell et al [51] obtained a direct energy gap of E g = 0.806 eV for ␤-FeSi 2 by PL at 5 K and then calculated the energy band gap of ␤-FeSi 2 at 300 K to be 0.811 eV after adjusting for temperature and acceptor level.…”

“…The energy band structure has been theoretically calculated in several literatures [1,6,7,[31][32][33][34] and the conduction type has been determined theoretically [30,[35][36][37][38][39][40][41] as well as experimentally in various literatures for undoped ␤-FeSi 2 . Almost in all cases of theoretical calculation of band diagram they have reported undoped ␤-FeSi 2 to be p-type [1,6,7,[31][32][33][34] as the Fermi level lies very close to valence band maxima whereas for experimental cases most of them reported undoped ␤-FeSi 2 to be p-type [30,[35][36][37][38]41] and few reported it to be n-type [35,39,40].…”

Epitaxial growth and optical characterization of compound semiconductor β-FeSi2 prepared by pulsed laser deposition

“…Among the nine types of compound semiconductors, b-FeSi 2 has attracted considerable attention for the applications in photovoltaic and thermoelectric devices [1,2], lightemitting diodes (LED) [3] and solar cells with theoretical efficiencies of 16-23% [4]. It also has a band gap of 0.80-0.81 eV region [5], good chemical-physical stability at high temperatures and high resistance to oxidation, and can be grown on Si substrates [6,7].…”

“…To prove the intrinsic A-band peak of the b-FeSi 2 comparison with the defect and dislocation-related band peaks (D and B), we have ascribed the energy band gap shift a value of the sample. Therefore, the PL properties of samples can be discussed by the Varshinis relationship as an empherical law in Eq (1). …”