Hydrogen Passivation of Luminescence-Quenching Defects in SiNanocrystals

Mechanism and enhancement of photoluminescence from silicon nanocrystals implanted in SiO 2 matrix

“…It is well known that hydrogen merely passivates DBs without changing the size and distribution of Si NCs in SiO 2 matrix. [14] In the precondition that all the PL spectra are measured under the same conditions, I R can reveal qualitatively the enhancement of PL efficiency of individual Si NCs. Moreover, DBs act as nonradiative recombination centres which quench the PL from Si NCs.…”

“…[6], interactions between Si NCs are also related to the density of Si NCs. Since hydrogen treatment hardly changes the size and distribution of Si NCs, [14] an additional factor that contributes to the monotonic increase in PL peak intensity is suggested.…”

“…As one of the methods, annealing in forming gas ambient (6% H 2 and 94% N 2 ) has been performed to passivate the interface states, such as the dangling bonds (DBs). The DBs act as nonradiative recombination centres [14] which reduce the efficiency of PL emission. However, with the increase in density of Si NCs in SiO 2 matrix, the DBs at the surface of neighbouring Si NCs become closer, and have influence on PL from Si NCs.…”

Relative enhancement of photoluminescence intensity of passivated silicon nanocrystals in a silicon dioxide matrix

“…The meaning of I R should be emphasized at first. Since hydrogen passivating merely eliminates DBs without changing the Si NCs, [17] the I R is related to the overlapping of the PL spectrum of Si NCs between different sizes, the size distribution of Si NCs, and the number of DBs. However, the overlapping of the PL spectrum of Si NCs with different sizes can be ignored since the width of PL spectrum of individual Si NC is far smaller than the wavelength scale concerned, especially when measured at low temperature.…”

“…[16] Many factors affect the PL process, such as defects, the degree of Si crystalliztion, phonons, dangling bonds (DBs), etc. In particular, DBs were determined to be nonradiative centers which quench PL, [17] but the role of DBs in the PL process has seldom been investigated in detail. In our previous work, [18] the PL intensity ratio (I R ) of passivated and unpassivated Si NCs suggests that the number of DBs on individual unpassivated Si NC was introduced to study the roles of DBs in the PL process.…”