Fabrication of efficient Ultraviolet Light Emitting Diodes (UV LEDs) is a challenging task for the semiconductor industry of the modern times. Finding the suitable semiconducting material is the key in order to make efficient LEDs. This book aims at understanding the use of ZnO in UV LEDs that demands the understanding of its optical properties first. Structural and optical properties of any semiconducting material are strongly correlated. An adequate knowledge and understanding of this relationship is necessary for fabrication of devices with desired optical properties. The aim of this work was to investigate the change in optical properties caused by growth techniques and substrate modification. To study the influence of growth technique on optical properties, ZnO nanostructures were grown using atmospheric pressure metal organic chemical vapor deposition (APMOCVD) and chemical bath deposition (CBD) techniques. Off-cut angle of SiC substrates were modified to observe the change on the optical properties. The results that are obtained demonstrate a significant contribution in the fields of ZnO based nano-optoelectronics and nano-electronics.