Quantum Confinement in Amorphous Silicon Quantum Dots Embedded in Silicon Nitride

Amorphous silicon quantum dots ( $a-\mathrm{Si}$ QDs) were grown in a silicon nitride film by plasma enhanced chemical vapor deposition. Transmission electron micrographs clearly demonstrated that $a-\mathrm{Si}$ QDs were formed in the silicon nitride. Photoluminescence and optical absorption energy measurement of $a-\mathrm{Si}$ QDs with various sizes revealed that tuning of the photoluminescence emission from 2.0 to 2.76 eV is possible by controlling the size of the $a-\mathrm{Si}$ QD. Analysis also showed that the photoluminescence peak energy $E$ was related to the size of the $a-\mathrm{Si}$ QD, $a$ (nm) by $E\left(\mathrm{eV}\right){=1.56+2.40/a}^2$, which is a clear evidence for the quantum confinement effect in $a-\mathrm{Si}$ QDs.