Microphotoluminescence and microphotoreflectance analyses of CO 2 laser rapid-thermal-annealed SiO x surface with buried Si nanocrystals
Journal
IEEE Transactions on Nanotechnology
Journal Volume
5
Journal Issue
5
Pages
511-516
Date Issued
2006
Author(s)
Abstract
The optical properties of a SiO x film rapid-thermal-annealed (RTA) by CO 2 laser are primarily investigated. The microphotoluminescence (mu-PL) and high-resolution transmission electron microscopy (HRTEM) analyses indicate that the precipitation of random-oriented Si nanocrystals can be initiated when laser intensity (P laser ) is larger than 4.5 kW/cm 2 . At P laser of 6kW/cm 2 , the Si nanocrystal exhibits a largest diameter of 8 nm and a highest density of 4.5times10 16 cm -3 , which emits strong PL at 790-825 nm. The microphotoreflectance of the CO 2 laser RTA SiO x film reveals a volume density product dependent refractive index increasing from 1.57 to 1.87 as P laser increases from 1.5 to 7.5 kW/cm 2 . Nonetheless, the laser ablation of the SiO x film occurs with a linear ablation slope of 35 nm/kW/cm 2 at beyond 7.5 kW/cm 2 , which terminates the enlargement of Si nanocrystals, degrades the near-infrared PL, and slightly reduces the refractive index of the CO 2 laser RTA SiO x film
Type
journal article