Effect of zno seed layer on the growth of zno nanorods via solution precipitation method
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Date
2018-06
Authors
Nik Anis Hafiza Nik Jusoh
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Abstract
There are various types of substrates that have been used to grow ZnO nanorods
on the surface. However, it is difficult to obtain highly aligned ZnO nanorods on Si
substrate because of the large mismatches between ZnO and Si. This problem could be
addressed by depositing a highly (002) oriented ZnO seed layer on the surface of Si
substrate. The seed layer of ZnO improved the coverage and aligned growth of ZnO
nanorods. In this project, ZnO seed layers were deposited on the Si substrate using spin
coating followed by post annealing in air. The precursors were zinc acetate dihydrate
dissolved in ethanol. The deposition of the seed layer was done at different cycles of
coating and different rotational speed (rpm) to improve the coverage of ZnO nanorods.
The SEM images shows that the highest number of coating cycles (11 cycles) and lowest
rpm (1000 rpm) has the best ZnO nanorods surface coverage on the substrate. For 1000
rpm, the percentage of ZnO nanorods surface coverage is 82.2%, while for 1000rpm at
11 coating cycles was 84.42%. The result showed that the lowest speed and highest
number of coating cycles provided the best coverage of ZnO seed layer. Next, ZnO
nanorods were synthesized from the pre-deposited ZnO seed layer via solution
precipitation method. Different annealing temperatures on the ZnO seed layer were
conducted to observe the differences of the alignment. The ZnO nanorods grown at 350oC
showed the best vertical alignment as the nanorods grew at c-axis.