Wide bandgap semiconductors have appeared as promising materials suitable for high-temperature, high-frequency and high power operations in electronic as well as optoelectronic devices because of their exceptional material characteristics. More specifically, these semiconductors possess an outstanding ability to materialize short wavelength light emitting devices due to their large band gap energy. Considered a useful class of materials with high stability and numerous useful properties, II-VI wide bandgap semiconducting oxide nanocrystals are widely used for optoelectronic applications especially LEDs and LDs in the short-wavelength visible-light region. However, as they are very strongly bonded with a nearly equal balance of covalent and ionic bonding, it is challenging to grow high-purity high-quality single crystals. In this book, the studies of properties of wide bandgap semiconductors are presented. Their structural, optical and electrical properties have been studied. Screen printing technique has been used as a multifaceted method for the fabrication of semiconductor layers in photovoltaic devices, especially II-IV compound semiconductors.