Strongly Confined Bi2Se3 Quantum Dots via Pulsed Laser Ablation in Liquids.

Bismuth selenide (Bi2Se3) is a binary compound displaying a strong spin-orbit coupling, resulting in a narrow bulk bandgap material with a gapless metallic surface. By shrinking the size of Bi2Se3 within the strong confinement regime, its optoelectronic properties changed drastically. To achieve this goal, strongly confined Bi2Se3 quantum dots (QDs) were produced by pulsed laser ablation in liquids (PLAL). The laser used for the synthesis was a nanosecond Nd/YAG laser emitting at 1064 nm and pulsing at ∼13 mJ/pulse. The irradiation of the bulk target was performed at 1 kHz in acetone and lasted 5 min. Finally, the Bi2Se3 QDs were spherical in shape with a diameter around 7 ± 3 nm and displaying an energy bandgap of 1.97 ± 0.19 eV.