Characterization of a β-FeSi 2 p–n junction formed by the PECS method

Abstract

We have fabricated semiconducting β-FeSi 2 bulks without doping and with Mn and Co doping by using a pulse electric current sintering (PECS) method, and explored the possibility of a direct bonding of n-type and p-type β-FeSi 2 bulks to form a p–n junction structure. P-type Mn-doped and n-type Co-doped β-FeSi 2 bulks were obtained by an annealing process at 800–850 °C for 100 h. The PECS was applied to bond the n-type and p-type bulks together for forming a p–n junction structure. We confirmed that the bonding was processed without any change in the β-FeSi 2 phase and was strongly joined with each other. Although we could not obtain the electrical characteristics of the p–n junction, Seebeck coefficients for n-type and p-type β-FeSi 2 in the bonded sample were determined to be −356 and 778 μV/K, respectively. We propose that these results should lead to an expanded use of the sintered β-FeSi 2 bulks in thermoelectric devices.