Emerging II-VI wide bandgap semiconductor device technologies

Abstract

The demand for advanced electronic and optoelectronic devices has driven significant research and development efforts toward exploring emerging semiconductor materials with enhanced performance characteristics. II-VI semiconductors have been studied extensively owing to their wide bandgap characteristics, which enable high electron mobility, excellent thermal stability, and resistance to radiation damage. These properties make them well-suited for a range of applications, including solar cells, light-emitting diodes (LEDs), photodetectors, lasers, sensors, and field effect transistors (FETs). In II-VI compounds, both ionic and covalent bonds exist with a higher electronegative nature of the VI-group elements than II-group elements. This existing ionic behavior strongly influences the binding of valence band electrons rather strongly to the lattice atoms. Thus, the II-VI semiconductors such as CdS, CdTe, ZnS, ZnSe, and CdSe possess wide tunable bandgaps (~0.02 to ≥ 4.0 eV) and high absorption coefficients of approximately 106 cm-1, setting them apart from other semiconductors formed by a covalent bond with closely equal atomic weights. This review article delves into the physics of II-VI semiconductor homo/heterojunctions, and the steps involved in device fabrication including lithography, etching, metallization, stability (oxidation and passivation) and polymerization together with several doping strategies. Furthermore, this review explores the process for tuning the distinct physical and chemical properties and a substantial advancement in electronic, and optoelectronic devices, including tools, cutting-edge equipment, and instrumentations. This comprehensive review provides detailed insights into the potential and technological progress of II-VI wide bandgap semiconductor device technology including experienced challenges and prospects.