Elaboration and characterization of thin layers of zinc oxide (ZnO) deposited by ultrasonic spray for photovoltaic and optoelectronic applications

Abstract

In this work we have developed thin layers of Zinc oxide (ZnO) by ultrasonic spray technique (SPU). We have modified some parameters such as the solution flow rate, the concentration of the solution, the substrate temperature (Ts), the tin concentration and the annealing temperature. The result obtained demonstrated that our ZnO films were crystallized according to the wurtzite hexagonal structure. For undoped layers deposited in deferent flow values from 50 ml / h up to 150 ml / h. the grain size decreased from 36.79 nm to 20.11 nm. The transmittance is about 80% in the visible range. The resistivity varies from 1.59 × 〖10〗 ^ (- 2) Ω.cm up to 43Ω.cm. for thin layers elaborated in deferent concentration value. The maximum transmittance value is 88% (the film thickness is 580 nm). The resistivity varied from 1.1 x 10-1Ω.cm up to 8.1 x 10-1Ω.cm. For thin layers made in deferent substrate temperature varied from 250 ° C to 500 ° C. The grain size was found to increase from 27.56 nm to 71.09 nm. The optical transparency is about 85%. The resistivity was decreased from 20 Ω.cm to 8.2 x 10-1Ω.cm. For thin layers deposited from changing the tin concentration, the grain size ranged from 12.85 nm to 39.18 nm. The transmittance is about 80%. The varied electrical resistivity from 43 Ω.cm to 1.2 x 10-2Ω.cm. The study of the annealing temperature has been indicated that the crystalline state of our thin layers will improve with increasing annealing temperature. The grain size varied between 12.9 nm and 46.94 nm. The varied electrical resistivity from 2.75 Ω.cm to 15 Ω.cm.