ﺑﺮرﺳﯽ ﺧﻮاص ﻓﯿﺰﯾﮑﯽ و اﺛﺮ ﻓﻮﺗﻮرﺳﺎﻧﺎﯾﯽ ﻧﺎﻧﻮﺳﺎﺧﺘﺎرﻫﺎي CuO ﺗﻬﯿﻪ ﺷﺪه ﺑﻪ روش اﮐﺴﺎﯾﺶ ﺣﺮارﺗﯽ

An Investigation on the Physical Properties and Photoconductivity Effect of CuO Nanostructures Prepared by Thermal Oxidation Route

ﻻﯾﻪﻫﺎي ﻧﺎزك اﮐﺴﯿﺪ ﻣﺲ ﺑﺮ روي زﯾﺮﻻﯾﻪ ITO ﺑﺎ اﺳﺘﻔﺎده از روش اﮐﺴﺎﯾﺶ ﺣﺮارﺗﯽ ﺗﻮﺳﻂ ﻻﯾﻪاي از ﻣﺲ ﮐﻪ ﺑﻪ روش روﻧﺸﺎﻧﯽ ﺑﺨﺎر ﻓﯿﺰﯾﮑﯽ (PVD) ﻻﯾﻪ ﻧﺸﺎﻧﯽ ﺷﺪه ﺑﻮد در دو ﺣﺎﻟﺖ ﺗﻬﯿﻪ ﺷﺪﻧﺪ: در ﻏﯿﺎب و ﺣﻀﻮر ﻻﯾﻪ ﭼﺴﺒﻨﺪه ﺑﺮ روي زﯾﺮﻻﯾﻪ. ﻧﻤﻮﻧﻪﻫﺎ ﺑﺎ اﺳﺘﻔﺎده از ﺗﺼﺎوﯾﺮ FESEM، ﻃﯿﻒﺳﻨﺠﯽﻫﺎي XRD و UV-Vis ﻣﻮرد ﻣﺸﺨﺼﻪﯾﺎﺑﯽ ﻗﺮار ﮔﺮﻓﺘﻨﺪ. درﯾﺎﻓﺘﯿﻢ ﻧﻤﻮﻧﻪي ﺑﺪون ﻻﯾﻪ ﭼﺴﺒﻨﺪه ﺑﻪ ﺻﻮرت داﻧﻪﻫﺎﯾﯽ ﻧﺎﻧﻮﻣﺘﺮي ﺑﺎ ﺳﻄﺤﯽ ﻧﺴﺒﺘﺎ ﺻﺎف و ﻧﻤﻮﻧﻪ ﺑﺎ ﻻﯾﻪ ﭼﺴﺒﻨﺪه از داﻧﻪﻫﺎﯾﯽ ﻣﺘﺨﻠﺨﻞ ﮐﻪ ﺧﻮد ﻣﺘﺸﮑﻞ از رﯾﺰداﻧﻪﻫﺎﯾﯽ در ﺣﺪود 30nm و ﯾﺎ ﮐﻮﭼﮑﺘﺮ ﺗﺸﮑﯿﻞ ﺷﺪه اﺳﺖ. ﻃﯿﻒﻫﺎي XRD ﻧﻤﻮﻧﻪﻫﺎ ﺣﺎﮐﯽ از ﺳﺎﺧﺘﺎر ﺑﺲﺑﻠﻮري در ﻓﺎز ﻣﻮﻧﻮﮐﻠﯿﻨﯿﮏ ﺑﺎ ﺟﻬﺘﮕﯿﺮيﻫﺎي ﺗﺮﺟﯿﺤﯽ (111) و (11̅1) ﻣﯽﺑﺎﺷﺪ. در ﺑﯿﻦ اﯾﻦ ﻧﻤﻮﻧﻪﻫﺎ، ﻧﻤﻮﻧﻪ ي ﺑﺎ ﻻﯾﻪ ﭼﺴﺒﻨﺪه از ﺷﺮاﯾﻂ ﻓﯿﺰﯾﮑﯽ ﻣﻨﺎﺳﺐﺗﺮي(اﺑﻌﺎد ﺑﻠﻮرﮐﯽ ﺑﺰرﮔﺘﺮ، ﮔﺎف ﻧﻮاري ﮐﻮﭼﮑﺘﺮ و ﺟﺬب ﻧﻮري ﺑﯿﺸﺘﺮ) ﺑﺮﺧﻮردار اﺳﺖ. ﺳﺮاﻧﺠﺎم، اﺛﺮﻓﻮﺗﻮرﺳﺎﻧﺎﯾﯽ در ﺳﺎﺧﺘﺎر ﻓﻠﺰ- ﻧﯿﻤﺮﺳﺎﻧﺎ- ﻓﻠﺰ (MSM) ﺑﺎ اﺳﺘﻔﺎده از ﻻﻣﭗ LED ﻗﺮﻣﺰ (nm 620) ﻣﻮرد ﺑﺮرﺳﯽ ﻗﺮار ﮔﺮﻓﺖ. ﻧﺘﺎﯾﺞ ﺑﺪﺳﺖ آﻣﺪه ﺣﺎﮐﯽ از آن اﺳﺖ ﮐﻪ ﻣﯿﺰان ﺣﺴﺎﺳﯿﺖ ﻧﻮري ﻧﻤﻮﻧﻪي ﺑﺎ ﻻﯾﻪ ﭼﺴﺒﻨﺪه در ﺣﺪود 3 ﺑﺮاﺑﺮ ﺑﯿﺸﺘﺮ از ﻧﻤﻮﻧﻪي ﺑﺪون ﻻﯾﻪ ﭼﺴﺒﻨﺪه ﺑﻮده، و ﺗﻐﯿﯿﺮات آن ﺑﺮ ﺣﺴﺐ ﺗﻮان اﻟﮑﺘﺮﯾﮑﯽ ﻻﻣﭗ ﺑﻪ ﺻﻮرت ﺧﻄﯽ ﻣﯽﺑﺎﺷﺪ.

Cupric oxide (CuO) thin films were synthesized on commercial ITO substrate using thermal oxidation route, a Cu-layer deposited by PVD method were prepared in two cases: in absence and in presence of an adhesive oxide layer on the substrate. Samples were characterized by FESEM images, XRD and UV-Vis. spectra. We found sample without adhesive layer is grown in the form of nano-grains with relatively slick surface, and the sample with adhesive layer is covered with porous grains containing small finegrains, about 30 nm or less. The XRD spectra of the samples indicate a polycrystalline structure in monoclinic phase with the main orientations of (111) and (􀀀111). Among these samples, the sample with presence of an adhesive layer has a better physical conditions (i.e. bigger crystallite sizes, smaller band gap and higher optical absorbance). Finally, photoconductivity effect in metal-semiconductor-metal (MSM) structure was investigated using a red (620 nm) LED lamp. The results showed that sensitivity of the sample with adhesive layer is about 3 times bigger than one without adhesive layer, and also its variation vs. lamp electrical power is linear.