Role of the interface region on the optoelectronic properties of silicon nanocrystals embedded inSiO2

Abstract

Light-emitting silicon nanocrystals embedded in SiO 2 have been investigated by x-ray absorption measurements in total electron and photoluminescence yields, by energy filtered transmission electron microscopy and by ab initio total energy calculations. Both experimental and theoretical results show that the interface between the silicon nanocrystals and the surrounding SiO 2 is not sharp: an intermediate region of amorphous nature and variable composition links the crystalline Si with the amorphous stoichiometric SiO 2. This region plays an active role in the light-emission process.

Silicon-rich SiO2/SiO2 multilayers: A promising material for the third generation of solar cell

“…[11][12][13][14] Besides the QC effect for explaining the new optical properties of nanometer-scaled Si films, some studies also pointed out the important role played by the Si/ SiO 2 interface in the PL. 13,[15][16][17] Thus, the PL of Si nanocluster ͑Si-ncl͒ is governed by key parameters such as grain size and the Si/ SiO 2 phase separation. An efficient absorption of light by the solar cell can be reached through the optimization of the density of Si-ncl, the Si-ncl size for a control of the absorbed wavelength of the solar spectrum, and the Si/ SiO 2 interface quality.…”

Energy transfer mechanism and Auger effect in Er3+ coupled silicon nanoparticle samples

“…Samples A and B likely contain Si amorphous nanocluster due to the low annealing temperature used which does not allow a complete phase separation and recrystallization of Si from the matrix. 21,22 This is confirmed by their broad luminescence spectra ͑see more later͒. Pieces of these samples, named A-re and B-re, respectively, have been annealed a second time at an higher temperature of 1100°C.…”

Combining Rare Events Techniques: Phase Change in Si Nanoparticles

“…The rationale for the upper limit of the Q 6 range is that the value of the bond-orientational order parameter for an ideal Si crystal is Q 6 = 0.63 and, since from experiments and previous calculations it is known that Si crystalline nanoparticles assume a structure with a (distorted) diamond-like core and a disordered periphery [23,24,25,26], we expect the Q 6 of crystalline nanoparticles be lower than this limit. The samples created according to the protocol described in Sec.…”