Single-dot spectroscopy of boron and phosphorus codoped silicon quantum dots

Boron (B) and phosphorous (P)codoped siliconquantum dots (SiQDs) are dispersible in polar solvents without organic ligands, and exhibit size controllablephotoluminescence(PL) from 0.85 to 1.85 eV due to the electronic transitions between the donor and the acceptor states. We study thePL spectra of thecodoped SiQDs at roomtemperature and at 77 K. We show that the broadPL band ofcodopedcolloidal SiQDs (full width at half maximum is over 400 meV) is composed of narrowerPL bands of individualQDs with differentPL energies. We also show that thePLlinewidth of individualcodoped SiQDs is almost twice as large as those of undoped SiQDs. In contrast to the significant narrowing of thePLlinewidth of undoped SiQDs at low temperatures, that ofcodoped SiQDs is almost independent of thetemperature except for a few very smallQDs. These results suggest that a large number of B and P aredoped in aQD and there are a number of non-identical luminescence centers in eachQD.

Source: Journal of Applied Physics - October 27, 2016 Category: Physics Authors: Takashi Kanno, Hiroshi Sugimoto, Anna Fucikova, Jan Valenta and Minoru Fujii Source Type: research