Rare-earth mono-pnictide (RE-V) nanoparticles embedded in Bi-alloyed III-V semiconductors and their alloys for THz device

Embedding rare-earth mono-pnictide (RE-V) nanoparticles, such as ErAs, into Bi-alloyed III-V semiconductors has been proposed for THz devices due to their ability to enhance properties by increasing phonon scattering, reducing thermal conductivity, and improving electrical conduction through electron filtering. Small amounts of Bi alloyed into III-V semiconductors significantly alter their electronic and optical properties, reducing the band gap and increasing spin-orbit splitting. Previous studies showed that the Fermi level is pinned at a similar energy on an absolute scale (with respect to vacuum) when considering band offsets between III-V compounds and their alloys with ErAs nanoparticles [1]. In this study, hybrid functional calculations on Bi-alloyed III-V semiconductors (III = Al, Ga, In; V = As) with 3.125% Bi show that Bi raises the valence-band maximum and lowers the conduction-band minimum. Hall measurements of ErAs nanoparticles in these Bi-alloyed semiconductors indicate Fermi-level positions that closely match our simulations, validating our theoretical predictions. Experimental results align well with the calculated trends in band structure modification and electronic behavior. These findings provide essential guidelines for designing nanocomposite materials with optimized optical, electronic, and thermoelectric properties for THz device applications.