III nitrides and UV detection

Abstract

III nitrides have become the most exciting challenge in optoelectronic materials in the last decade. Their intrinsic properties and an intense technological effort have made possible the fabrication of reliable and versatile detectors for short wavelengths. In this work, materials and devices issues are considered to provide a full picture of the advances in nitride UV photodetection. First, basic structures like photoconductors, Schottky, p-i-n and metal-semiconductor-metal photodiodes and phototransistors are compared, with emphasis on their specific properties and performance limitations. The efforts in the design and fabrication of more advanced detectors, in the search for higher quantum efficiency, contrast, signal-to-noise or speed operation, are reviewed afterwards. Metal-insulator-semiconductor diodes, avalanche photodetectors and GaN array detectors for UV imaging are also described. Further device optimization is linked with present materials issues, mainly due to the nitride quality, which is a direct result of the substrate used. The influence of substrates and dislocations on detector behaviour is discussed in detail. As an example of AlGaN photodetector applications, monitoring of the solar UV-B radiation to prevent erythema and skin cancer is presented.

Solid-State Lighting Based on Light Emitting Diode Technology

“…Possible applications of UV optoelectronics include water purification, pollution monitoring, UV astronomy, chemical/biological reagent detection and flame detection [8,103].…”

Enhanced UV detection by non-polar epitaxial GaN films

“…3 The large and direct band gap of III-nitride materials are proving very advantageous for UV photodetection and a lot of interest to further improve the performance of photodetectors fabricated on III-nitride material is seen in the past few years. 4 First UV photodetector of GaN was reported by Khan et al in 1992. 5 Lack of suitable substrates for the growth of GaN has been a prolong problem and this is a main hindrance in improving the quality of the optoelectronic devices hence fabricated.…”

Junction Properties and Applications of ZnO Single Nanowire Based Schottky Diode

“…Surface plays a crucial role to determine the electrical and optoelectronic properties of materials with a dimension of nanometer scale. There are several wide bandgap semiconducting materials for UV detection like GaN, ZnO, AlGaN (Munoz et al, 2001;Soci et al, 2007;Li et al, 2009). Because of their wide bandgap and high surface-to-volume ratio, nanoscale electronic devices have the potential to achieve high sensitivity and faster response for the UV detection.…”