Coalescence threshold temperature in Ag nanoparticles growth by pulsed laser deposition |
Paper ID : 1352-UFGNSM-FULL |
Authors: |
Abstract: |
In this study, Ag nanoislands were deposited on glass and Si(100) at substrate temperature from 25 to 450 °C by Pulsed Laser Depositions (PLD). The growth of Ag nanoislands was evidenced from the appearance of optical absorption surface plasmon resonance (SPR) bands. SPR peaks was not evidently observed in the spectrum of sample deposited at 25 ˚C, but sample deposited at 150 ˚C presented a broad SPR peak around λ=870 nm. The resonance peak showed a blue shift to 540-550 nm and become narrower as the substrate temperature increases to 250, 350 and 450 ˚C. Surface morphology of Ag films was investigated by means of Atomic Force Microscope (AFM). The resulting images showed that by increasing deposition temperature to 350 and 450 ˚C, these Ag islands grow in height and diameter, and at the same time, the number of island decrease among the surface. Two-probe measurement of electrical resistance of films was also recorded during deposition processes to recognize the coalescence of Ag nanoislands. The results show that the deposition at temperatures below 250 ˚C leads to a sharp decrease in film resistance while at higher temperatures the islands were separated without giving any resistance decline. To determine exactly a threshold temperature of coalescence for our deposition conditions, resistance variation was monitored during deposition Ag on an under cooling, from 300 down to 200 ˚C, substrate. The result revealed that the coalescence of Ag begins near 230 ˚C. |
Keywords: |
Ag nanoisland, PLD, Coalescence, SPR, Resistance measurment |
Status : Paper Accepted (Poster Presentation) |