Mohanta S K, Soni R K, Tripathy S, Chua S J, Kanjilal D
Department of Physics, Indian Institute of Technology, New Delhi 110016, India.
J Nanosci Nanotechnol. 2007 Jun;7(6):2046-50. doi: 10.1166/jnn.2007.766.
The InP nanodots of size 55 to 100 nm and height 25 to 30 nm have been synthesized by low-energy Ar+-ion irradiation with different ion energies. Sizes and size distributions of the dots strongly depend on growth conditions. Rapid thermal annealed (RTA) of the patterned surface shows cluster formation for annealing temperature 400 degrees C and above. Raman investigations reveal optical phonon softening due to correlation length shortening and broadening of the optical modes from the patterned surface. The softening is due to confinement of phonons in embedded nanocrystallites within the patterned surface along with surface nanodots, and broadening is attributed to their size distributions, which increases with increase in ion energy. The lattice damage recovery is observed from the patterned surface subjected to RTA, which exhibits upward shift of the LO and TO phonons due to the presence of complex interfacial stress, associated with the removal of crystal defects with RTA.
通过不同离子能量的低能Ar⁺离子辐照合成了尺寸为55至100纳米、高度为25至30纳米的磷化铟纳米点。这些点的尺寸和尺寸分布强烈依赖于生长条件。对图案化表面进行快速热退火（RTA），结果表明在退火温度为400摄氏度及以上时会形成团簇。拉曼研究揭示，由于相关长度缩短以及图案化表面光学模式的展宽，导致光学声子软化。这种软化是由于声子被限制在图案化表面内的嵌入纳米微晶以及表面纳米点中，而展宽则归因于它们的尺寸分布，尺寸分布会随着离子能量的增加而增大。从经过RTA处理的图案化表面观察到晶格损伤的恢复，由于存在复杂的界面应力，与RTA去除晶体缺陷相关，导致LO和TO声子出现向上位移。
