Fabrication and characteristics of heavily fe-doped LiNbO3/Si heterojunction

Abstract

A series of heavily Fe-doped LiNbO3 (LN:Fe) crystals were grown via the Czochralski method. The dark- and photo-conductivity of the 5.0 wt.% Fe-doped LiNbO3 crystal reached 3.30 × 10-8 Ω-1 cm-1 and 1.46 × 10-7 Ω-1 cm-1 at 473 nm, which are about 7 and 5 orders of magnitude higher than that of congruent LiNbO3, respectively. Then, a p-n heterojunction was fabricated by depositing the heavily Fe-doped LiNbO3 on a p-type Si substrate using the pulsed laser deposition. The current-voltage curve of the LN:Fe/Si heterojunction presents a well-defined behavior with a turn-on voltage of 2.9 V. This LN:Fe/Si heterojunction gives an excellent prototype device for integrated optics and electro-photonics.