Role of Metal-semiconductor Heterojunction in Photoluminescence of Bi/Bi₂O₃ Nanoparticles
Ranjit A. Patil1*, Yuan-Ron Ma1
1Department of Physics, National Dong Hwa University, Hualien, Taiwan
* presenting author:Ranjit A. Patil,
In this work we elaborate and discussed the heterojunction-assisted photoluminescence (PL) mechanism in Bi/Bi2O3 metal-semiconductor nano-system. The Bi/Bi2O3 heterojunction nanoparticles of various sizes are synthesized using the pulsed Nd:YAG laser deposition technique at various substrate temperatures. The Bi/Bi2O3 heterojunction nanoparticles consist of the Bi nanoparticles and Bi2O3 surface layers. The average diameter of the Bi nanoparticle and the thickness of the Bi2O3 surface layer linearly varies with the substrate temperature. When the incident laser gives thermal energy to the free electrons of the metallic Bi nanoparticles, they easily overcome the Ohmic barrier and move to the surface layers of n-type Bi2O3. Because the metallic Bi nanoparticles provide the majority free Fermi-level electron for the electron-hole recombination in the Bi₂O₃ surface layers of Bi/Bi2O3 heterojunctions, PL emissions of the Bi/Bi2O3 nanoparticles are enhanced strongly.

Keywords: Bi/Bi2O3, nanoparticles, pulsed laser deposition (PLD), metal-semiconductor heterojunction, photoluminescence