Photoluminescence Mechanism of Silicon Quantum Dots and Wells

Abstract

We discuss the mechanism of efficient photoluminescence (PL) from Si quantum dots and wells. Luminescence properties of Si0 2 -capped Si nanocrystals are different from those of H-terminated Si nanocrystals, but are very similar to those of Si quantum wells sandwiched by Si0 2 layers. The size-dependence of PL properties and resonantly excited PL spectra of SiO 2 -capped Si dots and wells indicate that excitons are localized near the interface between the crystalline Si core and surface oxide layer, and the strong coupling of electronic and vibrational excitations causes the broad PL spectrum. The exciton localization plays an essential role in the efficient luminescence process in nanoscale Si/SiO 2 systems.

Correlation between structural and optical properties of nanocrystal particles prepared at low temperature by plasma-enhanced chemical vapor deposition

“…The increase in the deposition temperature causes the decrease of the PL peak energy. In this case, the band gap energy of the crystalline core state is lower than the -1.65 eV interface state [5]. The size-dependent PL characteristics in hydrogenated nanocrystals is result in presence delocalized states in the Si crystalline core.…”

Mechanism for pillar-shaped surface morphology of polysilicon prepared by excimer laser annealing

“…Quantum confinement has been attributed to some observed luminescence and enhanced nonlinear optical properties. 14,15 Various methods, including pulsedlaser ablation, 16 laser-induced gas phase reaction, 17 sizeexclusion methods, 18 ion implantation, 19 and spark processing, 20 have been used to prepare Si nanoclusters. By making use of the pillars discussed above, a simple method is proposed to prepare silicon quantum dots.…”