ﺗﺎﺛﯿﺮ ﺷﺮاﯾﻂ رﺷﺪ ﺑﺮ آراﯾﻪ ﻧﺎﻧﻮﻣﯿﻠﻪﻫﺎي ﻫﻤﺮاﺳﺘﺎي ZnO

Effect of Growth Condition on Charactristic of ZnO nanorods

آراﯾﻪ ﻧﺎﻧﻮﻣﯿﻠﻪﻫﺎي ﻫﻤﺮاﺳﺘﺎ ZnO ﺑﻪ روش ﻧﻬﺸﺖ ﺣﻤﺎم ﺷﯿﻤﯿﺎﯾﯽ در دﻣﺎي ﭘﺎﯾﯿﻦ ﮐﻤﺘﺮ از (120oC) ﺑﻪ ﮐﻤﮏ ﻻﯾﻪﺟﻮاﻧﻪزﻧﯽ در ﺷﺮاﯾﻂ ﻣﺨﺘﻠﻒ ﻣﺎﻧﻨﺪ دﻣﺎ و ﻏﻠﻈﺖ ﺣﻤﺎم، ﺿﺨﺎﻣﺖ ﻻﯾﻪ ﺟﻮاﻧﻪزﻧﯽ و ﺑﺎزﭘﺨﺖ آن رﺷﺪ ﮐﺮدهاﻧﺪ. وﯾﮋﮔﯽﻫﺎي ﺳﺎﺧﺘﺎري، رﯾﺨﺘﯽ و ﺷﯿﻤﯿﺎﯾﯽ، و اﭘﺘﯿﮑﯽ آراﯾﻪ ﻧﺎﻧﻮﻣﯿﻠﻪﻫﺎي ZnO ﺑﻪ ﺗﺮﺗﯿﺐ ﺑﻪ وﺳﯿﻠﻪ ﭘﺮاش ﺳﻨﺠﯽ ﭘﺮﺗﻮ X ، ﻣﯿﮑﺮوﺳﮑﻮپ اﻟﮑﺘﺮوﻧﯽ روﺑﺸﯽ- ﮔﺴﯿﻞ ﻣﯿﺪاﻧﯽ ﺑﻬﻤﺮاه ﻃﯿﻒﺳﻨﺠﯽ ﭘﺮﺗﻮ X ﺑﺎ ﭘﺎﺷﻨﺪﮔﯽ اﻧﺮژي (FE-SEM/EDX) و ﻃﯿﻒ ﺳﻨﺠﯽ ﺟﺬﺑﯽ UV-Vis-near IR ﺑﺮرﺳﯽ ﻣﯽﺷﻮﻧﺪ. ﻋﻤﻠﯿﺎت ﺣﺮارﺗﯽ ﭘﺲ از ﺳﻨﺘﺰ ﻧﺎﻧﻮﻣﯿﻠﻪﻫﺎ اﻓﺰاﯾﺶ در ﮐﯿﻔﯿﺖ ﺑﻠﻮري ﻧﺎﻧﻮﻣﯿﻠﻪﻫﺎي رﺷﺪ ﯾﺎﻓﺘﻪ ﺑﺎ ﺟﻬﺖﮔﯿﺮي ﺗﺮﺟﯿﺤﯽ ﻋﻤﻮدي C ﺑﻪ دﻧﺒﺎل دارد. ارﺗﻔﺎع، ﻗﻄﺮ ﻣﯿﺎﻧﮕﯿﻦ و ﭼﮕﺎﻟﯽ ﻧﺎﻧﻮﻣﯿﻠﻪﻫﺎي ﺑﻪ ﺷﺪت ﻫﻤﺮاﺳﺘﺎ ﺑﺮ ﻻﯾﻪ ﺟﻮاﻧﻪزﻧﯽ ZnO ﺑﻪ ﺗﺮﺗﯿﺐ در ﺣﺪود 52-31nm ،190nm و 413-290 rods)/µm) ﻣﯽﺑﺎﺷﻨﺪ. ﺑﺎزﭘﺨﺖ ﻧﺎﻧﻮﻣﯿﻠﻪﻫﺎ در دﻣﺎي 400oC ﺑﺎﻋﺚ ﮐﺎﻫﺶ اﻧﺮژي ﮔﺎف ﻧﻮاري از ﻣﻘﺪار 3/29eV ﺑﺮاي ﻧﺎﻧﻮﻣﯿﻠﻪﻫﺎ ﺑﺪو-رﺷﺪ ﺑﻪ ﻣﻘﺪار 3/19eV ﻣﯽﺷﻮد. اﻓﺰاﯾﺶ دﻣﺎي ﺣﻤﺎم ﺷﯿﻤﯿﺎﯾﯽ ﺗﺎ 110oC ﺑﺎﻋﺚ ﺟﻬﺖﮔﯿﺮي رﻧﺪوم ﻧﺎﻧﻮﻣﯿﻠﻪﻫﺎ و ﮐﺎﻫﺶ اﻧﺮژي ﮔﺎف ﻧﻮاري ﻣﯽﺷﻮد. ﺑﺎزﭘﺨﺖ ﻻﯾﻪ ﺟﻮاﻧﻪزﻧﯽ در ﺑﺎزه دﻣﺎﯾﯽ -200oC 600 ﺑﺎﻋﺚ ﮐﺎﻫﺶ در ارﺗﻔﺎع ﻧﺎﻧﻮﻣﯿﻠﻪﻫﺎ، اﻓﺰاﯾﺶ در ﻗﻄﺮ ﻣﺘﻮﺳﻂ و ﮐﺎﻫﺶ در ﺗﺮاﮐﻢ و ﻫﻤﯿﻨﻄﻮر ﮐﺎﻫﺶ در اﻧﺮژي ﮔﺎف ﻧﻮاري ﻣﯽﺷﻮد. ﮐﺎﻫﺶ در ﺿﺨﺎﻣﺖ ﻻﯾﻪ ﺟﻮاﻧﻪزﻧﯽ ﺑﺎﻋﺚ ﮐﺎﻫﺶ در ﻗﻄﺮ ﻧﺎﻧﻮﻣﯿﻠﻪﻫﺎ و اﻓﺰاﯾﺶ ﺗﺮاﮐﻢ آنﻫﺎ ﻣﯽﺷﻮد.

Well-aligned ZnO nanorods array have been synthesized through chemical bath deposition at law temperature (less than 120oC) using seed layer under different condition such as bath concentration and temperature, growth time, thickness of seed layer and it’s annealing. Structural, morphological, chemical and optical properties of ZnO nanorods array were studied by X-ray diffractometry, field emission-scanning electron microscopy/energy dispersive X-ray spectroscopy (FE-SEM/EDX) and UV-Vis-near IR optical absorption spectroscopy, respectively.The post-synthesized thermal treatment results in increased crystalline quality of nanorods as vertical c preffered orientation. The height, mean diameter and density of strongly well-oriented ZnO nanorods array are 190nm, 31-52 nm and 290-413 rods/μm2 on ZnO seed layer, respectively. The annealing of nanorods at 400oC causes to decrease in bandgap energy from 3.29eV for the as-grown nanorods to 3.19 eV. The increase in bath temperature to 110oC results in random direction of nanorods and decreasing in bandgap energy. The annealing of seed layer at temperature range of 200-600oC causes to increase in mean diameter and decrease in nanorods height and concentration and bandgap energy. The decrease in seed layer thickness causes to decrease in nanorods concentration.