Dear Dzetty soraya abdul aziz 

Increasing the substrate temperature leads to increasing the crystallite size of deposited samples. Where increasing the T sub leads to increase the thermal energy of the sample, this thermal energy helps in rearranging the crystallites to form agglomerations of crystallites. As a result they will form the NWs. The size of these agglomerations will consequently increased, so the diameter of NWs will increased with Tsub.

I hope this may help you

Dear Ahmed Saeed,

Thanks very much for the valuable answer. yes it really helps:)

Dear colleague Dzetty soraya abdul aziz 

Have a nice time and good day.

I want to thank Prof. Dr. Ahmed Saeed Hassanien for his good presentation.

The structural, optical and electrical properties of materials depend on many parameters; material state (amorphous, poly crystalline and crystalline), type of materials (organic or inorganic), materials form (liquid, thin film, powder or bulk),  preparation method, type of container, thermal history, aging, Structural relaxation.....e.t.c. 

The thermal history of the prepared material is one of the most important parameters that may affect the properties of the produced material. 

Ex. 1- Bulk materials that prepared by quenching in iced water and thin films that prepared on substrate at room temperature or less may has a short range order or amorphous nature, it may also has nano structure or as amorphous; no crystallite size or certain arrangement. Such those materials have the tendency to structural relaxation. Those materials are also stressed; atoms are randomly arranged which produces defects or dangling bonds forming localized states or highly disordered materials.

 2- Bulk materials that prepared by Bregman method (slow cooling rate) and thin films that prepared on substrate at different temperatures have small structural relaxation and less stressed. Through the two mentioned methods, the prepared materials give enough time to the atoms to take its time to satisfy saturated bonds at the expense of unsaturated bonds which decreases the dangling bonds or disorder and consequently the medium and long range order may be introduced. As a resultant, nucleation of different shapes of crystallite size will be introduced. More slow cooling rate of bulk materials and high substrate temperature will give the chance of small crystallite size to merge with each other to form large size and consequently grain size with different high diameters will be appeared with high quality poly crystalline structure ( nano crystals or nano wires or other). The more slow cooling rate of bulk materials and high substrate temperature will enhance the structural properties and may all crystallite sizes merged together to form single crystal with high diameter.      

I wish this is useful and help you.

Yours

A. El-Denglawey