Study On Photoelectric Properties Of Non-polar Surface AlGaN/ZnO Heterojunction Polarization Luminescence/Detection Dual Function Devices

Polarized ultraviolet luminescence and detection have important application value in special applications such as UV polarization exposure,cosmic background radiation detection,and atmospheric analysis.Nonpolar a-ZnO materials are suitable for the preparation of polarized UV optoelectronic devices due to their high exciton binding energy?60 meV?,wide direct bandgap?3.37 eV?and natural polarization optical anisotropy.Dual-function devices capable of simultaneous illumination and detection have tremendous value in the field of multifunctional devices due to simpler structure and high integration.Many problems lie in the preparation polarized light emitting and detecting dual-function devices based on nonpolar a-ZnO materials.It is difficult to prepare high-quality nonpolar p-AlGaN and n-ZnO materials.The stress applied by the substrate/template material makes the polarization optical properties of ZnO are uncontrollable.For the heterojunction based on GaN/ZnO,the introduction of heterogeneous interlayers to achieve ZnO dominant luminescence leads to deterioration of crystal quality.Luminescence and detection belong to the opposite photoelectric conversion process,and it is difficult to achieve monolithic integration.Based on the epitaxial growth of nonpolar a-plane p-AlGaN/n-ZnO heterojunction materials,this paper aims to realize the model of light emission and detection dual-function devices and duplex optical communication systems by optimizing the AlGaN and ZnO epitaxial growth processes to improve surface morphology and crystal quality.This paper applied different in-plane stresses to explore its optical anisotropy regulation and introduced p-AlGaN to increase the spatial overlap ratio of the electron hole wave function in the ZnO region.Designing and implementing the reverse illuminating LED based on the tunneling effect and realize duplex communication optoelectronic device by Crosslight software simulation.The main contents of this thesis include the study of the stress control rule of the template on the optical anisotropy of the ZnO material,the preparation of the ZnO heterojunction LED chip based on p-AlGaN,the microscopic mechanism study of the illumination enhancement of i-ZnO later,summarized in three aspects:?1?The epitaxial growth temperature conditions of non-polar a-plane AlGaN materials were studied,and the p-type doping was studied.The a-ZnO thin films were heteroepitaxially grown.The regulation of in-plane optical anisotropy was studied by characterization of materials,polarization photoluminescence spectroscopy and polarization Raman spectroscopy.Furthermore,the effects of template stress on the optical anisotropy of Mg_xZn_1-x-x O films and the effects of MgZnO intercalation layers on the optical anisotropy of n-ZnO materials were investigated.?2?The photoelectric properties of p-AlGaN/n-ZnO heterojunction LEDs were systematically studied and analyzed,and the effects of the reverse luminescence mechanism and template quality on the final device performance were clarified.On the other hand,the off-axis electron holography technology was used to explain the luminescence enhancement mechanism of p-AlGaN/i-ZnO/n-ZnO heterojunction LEDs.?3?Based on the Crosslight simulation,a dual-function device with both luminescence and detection functions was designed and fabricated.The reverse luminescence and detection characteristics and mechanism were characterized and analyzed.The reverse tunneling collision electrode mechanism was verified by Crosslight simulation.Finally,a set of light-based information transmission and reception duplex communication system was designed,and the simulation function demonstration case is realized through the web front-end technology.The innovations of the above research contents lie in:?1?The DOP of a non-polar ZnO material PL based on heterogeneous epitaxial growth of GaN and AlGaN templates which can be used as a p-type material was measured,revealing the influence of internal stress on optical anisotropy.Further,an anisotropic concept of the crystal quality of a non-polar surface semiconductor material was proposed to quantitatively evaluate the relationship between the in-plane anisotropy of crystal quality and optical anisotropy.?2?The nonpolar a-plane p-AlGaN/n-ZnO heterojunction LED chip device was fabricated,and the avalanche luminescence of the device under reverse bias was observed.For the enhancement of device performance of i-ZnO intercalation layer,the potential microscopic mechanism behind was revealed from the nanometer scale by means of spectral characterization,microstructure characterization and electrostatic potential distribution measurement.?3?A ZnO-based polarized luminescence and detection dual function device was prepared.Nonpolar n-ZnO/i-ZnO/p-?Al?GaN structures grown on optically transparent sapphire substrates have not been reported in terms of device structure.