Cuprous oxide (Cu2O) is a semiconducting, cubic crystal structure, inexpensive and low toxicity nature with relatively low direct band gap of about 2.0 2.6 eV [1, 2]. Furthermore, it has superior photo electronic properties, abundantly available and simple preparation procedures [3, 4]. Cu2O has a unique cuprites structure through a body-centered cubic packing of copper atoms with oxygen atoms occupying the tetrahedral sites [5, 6]. Cu2O is of interest and received great attention due to encouraging use in several application and technological fields. In general, Cu2O and CuO materials are semiconductors p-type, thus potentially useful for fabricating junction devices for example p-n junction solar cell and diodes [7-9]. In addition, their use in heterogeneous catalysts for solid state gases sensor heterocontacts [10-12], microwave dielectric materials , and several environmental processes . Furthermore, copper oxides have been employed in various applications such as power sources , photovoltaic devices , antibacterial activity , as well as these material have been used in lithium batteries as electrode materials [18-20].
The synthesized methods of Cu2O films can be mainly divided into two groups, namely physical and chemical methods. Among these methods, chemical preparation methods such as electro-deposition , sol–gel method , spray pyrolysis , Pulsed Laser Deposition [24, 25] and chemical bath deposition (CBD) . CBD is one of the traditional methods of chemical or physical deposition, where the preparation of Cu2O using CBD method has many unique and excellent properties compared with other synthesized methods, such as operated at low temperature, low-cost equipment, high deposition rate and high quality of the deposited films [21-23, 27], as well as easy control of growth parameters and excellent adhesion to substrate with depositing with large-area films [26, 28].
Size control is one of the most effective requirement in wide range of applications requires the control of the size and geometry of nanoparticles which in turn lead to control of optical and electrical properties [29, 30]. Therefore, the growth and tailoring of Cu2O or CuO to produce surface densities, shapes and specific sizes have been broadly focused and studied due to their various applications [31-33]. Many important researches have been carried out using CBD deposition method to preparation Cu2O nanoparticles under multiple mechanisms and growth conditions and parameters . For example, Saadaldin et al.  fabricated copper oxide thin films at different substrate annealing temperatures of 200, 300, 400 °C, respectively, in the air by CBD deposition method at 70 °C; the properties of prepared of copper oxide films were related to annealing temperature. Sultana et al.  reported CuO thin films with different thicknesses (60 nm to 178 nm) on silicon (n-Si) substrate by CBD method at 85°C. Effects of adjusting the growth time on the optical and structural properties, chemical composition, and structural quality of CuO films has been achieved. In addition, the CuO thin films at 110 nm thicknesses showed the best crystal quality, dielectric constant, refractive index, and optical properties. Reyes, et al.  reported uniform and crystalline thin film of Cu2O on corning glass substrates coated CuxS seed layer by CBD method; the effect of pH and growth temperature (≤ 70°C) on the electrical, morphological, optical and structural properties of Cu2O thin film was investigated. In addition, increase of growth temperature lead to increases the stimulates the morphologies formation and thickness, which reduces the band gap and enhances transmittance [38- 40].
The thin film of indium-doped tin oxide (ITO) which used as seed layer shows a critical role in determining the growth process of nanoparticle synthesis a high-quality of is necessary for growth process of the semiconductor films with good crystal quality [38-41]. The relationship between the seed layer and nanostructure films must be studied due to the properties of the nanostructure which are depend mainly on the properties of seeds, such as roughness, crystalline density morphology, crystalline, and grain size [42-45]. Therefore, synthesis a seed layer with high-quality most attractive method toward synthesize of cuprous oxide films, which have the ability to promote the development of novel devices and potential applications [46-49]. Therefore, numerous recent researches in the literature have informed influence of seed layer-assisted chemical bath deposition (SCBD) method on growth of Cu2O and CuO nanostructures. Zhu, et al.  reported on CuO thin films on CuO seed layers and ITO coated glass substrate through SCBD method.. Forat, et al.  reported Cu2O flowers grown on ITO seed layer coated glass substrate using SCBD at 70 °C; ITO seeds with thickness of 75 nm prepared on glass substrates using magnetron sputtering-RF. The results exhibited that the Cu2O film was good crystallinity, grow in the cubic structure, and uniformly formed on seeds/glass substrates. Muiva, et al.  reported on the growth of one dimensional CuO nanostructures films through SCBD method on CuO seed layers deposited by two methods; chemical spray pyrolysis (CSP) method and successive ionic layer adsorption (SILAR) techniques coated float glass substrates. The CSP/CBD film yielded large grain size and lees strained than the SILAR/CBD film. The average grain sizes were found to be 35.8 nm and 11.9 nm for the CuO nanostructures deposited on CSP and SILAR CSP seed crystals, respectively.
The seed layer can be affected by affecting its properties by using multiple mechanisms and growth conditions and parameters, thickness, quality, and heat treatment process. Laser annealing temperature of seed layer is considered one of the critical conditions for controlling the properties of nanostructure films and reduce or remove the damage of semi-conductor surfaces come to be a more interesting topic for researchers at 1977 . High power laser beam quickly heats the surface regions of semiconductor films to a high temperature or dissolves them above melting temperatures. The CW laser or pulsed leads to directed energy procedures characterized within a short time by energy dropping on the surface of nanoparticle semiconductor. The surface of the nanoparticles with rapidly heating and cooling might lead to a really homogeneous form of film surface. Laser annealing using continuous or pulsed wave depends on various conditions that leads to melting surface of semiconductor film as resulted from the absorption of light energy which converted to heating. This heat energy is transmitted to the electronic structure and then to phonons rapidly with less than of 1 Psec [54, 55].
In this work, Cu2O nanoparticles growth using SCBD method employing the thermal effect of CW Carbon dioxide laser to annealed the seed layer and then controls the morphological, optical, and structure properties are presented for the first time.