Abstract
Undoped ZnO and group III (B, Al, Ga, and In)-doped ZnO thin films at 3% doping concentration level are dip-coated on glass substrates using a sol-gel technique. The optical properties of the as-prepared thin films are investigated using UV–Vis spectrophotometer measurements. Transmittance of all investigated thin films is found to attain high values of ≥80% in the visible region. We found that the index of refraction of undoped ZnO films exhibits values ranging between 1.6 and 2.2 and approximately match that of bulk ZnO. Furthermore, we measure and interpret nonlinear optical parameters and the electrical and optical conductivities of the investigated thin films to obtain a deeper insight from fundamental and practical points of view. In addition, the structural properties of all studied thin film samples are investigated using the XRD technique. In particular, undoped ZnO thin film is found to exhibit a hexagonal structure. Due to the large difference in size of boron and indium compared with that of zinc, doping ZnO thin films with these two elements is expected to cause a phase transition. However, Al-doped ZnO and Ga-doped ZnO thin films preserve the hexagonal phase. Moreover, as boron and indium are introduced in ZnO thin films, the grain size increases. On the other hand, grain size is found to decrease upon doping ZnO with aluminum and gallium. The drastic enhancement of optical properties of annealed dip-synthesized undoped ZnO thin films upon doping with group III metals paves the way to tune these properties in a skillful manner, in order to be used as key candidate materials in the fabrication of modern optoelectronic devices.
Highlights
In the past two decades, the synthesis, design, and characterization of III-V and II-VI semiconductors have fascinated several research groups around the globe
The measured transmittance of Al-doped ZnO thin films is in good agreement with the findings reported in [16,20]
III elements-doped (B, Al, and In) thin films were of fabricated at a 3% doping
Summary
In the past two decades, the synthesis, design, and characterization of III-V and II-VI semiconductors have fascinated several research groups around the globe. ZnO is considered to be a very important semiconductor material due to its fundamental and physical properties It has been reported and implemented as a key candidate material for potential applications in optoelectronic devices, photovoltaic devices, gas sensors, light. It is unusual for ZnO to have an exciton binding energy of 60 meV This large value is very interesting, as it is useful for the development of many optoelectronic devices. In the photoluminescent spectrum of ZnO, very sharp emission peaks are observed, due to excitonic radiative recombination processes. These types of emissions have many possible applications, such as UV excitonic lasers, tunable UV photodetectors, and light emitting diodes. ZnO has good transparency in the visible range spectrum and large electrical conductivity [10,11]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
