High-brightness and deep-ultraviolet (UV) light-sources with emission wavelengths ranging from 230~350 nm (3.54~5.39 eV) have various applications that include water purification, air sterilization, medical and bio-agent detection, skin treatment, white-light illumination, and light sources for high-density optical storage. The purpose of this study is on the synthesis of Aluminum Oxynitride (AlON)-based materials, which emit in the UV region, as well as fabrication of a novel UV light emitter using those AlON materials by printing method.
In the chapter 1, I have explained the importance of UV emitters, the problem of present UV emitters, and the purpose of this study. Moreover, field emission devices and printed electronics that are the basic information of this study have been introduced.
In the chapter 2, synthesis of AlON powders for the ultraviolet (UV) emitter application have been investigated. I have sintered several AlON’s by varying the growth conditions and raw powder composition. Also, This chapter provided how to make a UV field emitting device. I have applied ZnO, AlN and produced AlON powders as a UV emitting layer using screen printing method. A CNT field emission array was used as an excitation source. Finally, I have briefly explained the measurement methods used in this study.
In the chapter 3, the shape, chemical composition, phase analysis, luminescence properties and structural characterizations of produced AlON have been characterized by SEM, EDS, XRD, CL, and TEM. In this chapter, I have found the emission wavelength of AlON could be tuned from 4.29 to 4.54 eV (289 to 272 nm) by changing the synthesizing conditions. A core-shell structure was confirmed for the AlON particles.
In the chapter 4, I have characterized the properties of AlON UV field emitter. The current voltage (I-V) curve for the field emitter was monitored using a high-voltage supply and a picoammeter, and the UV light spectrum was recorded using a photon multiplier tube (PMT) and a monochromator system. In this chapter, It is confirmed that the device performance of a AlON-UV field emitter fabricated via a simple screen-printing technology was comparable to other field emission optoelectronics. I observed a strong UV luminescence from the device centered at 3.68 eV (337 nm). The origin of this luminescence is believed to derive from the local minimum state of the N-rich AlON, which was placed in the inner side of the naturally formed core-shell structure.
In the chapter 5, results of this study have been summarized.
Through this study, I have discovered the promising UV emitting material: AlON, and proved that the convenient novel UV device, which is introducing in this thesis has potential to be used for various applications in UV market in the future.