Research On Analysis And Application Of Photoluminescence Of HVPE-GaN

Gallium nitride(GaN) is a direct and wide bandgap compound semiconductor material composed of group ? element Ga and group?element N.With stable physicochemical properties,and excellent photoelectric properties,GaN is not only an ideal material for the fabrication of high performance light emitting devices,but also one of the key materials for the preparation of optoelectronic devices and high power devices.Hydride vapor phase epitaxy(HVPE) is the most potential growth method to realize the industrialization of GaN bulk materials.Photoluminescence test is easy to operate,non-destructive and highly sensitive.It is a basic and necessary traditional test method in the production and research of semiconductor materials and devices.It is of great significance to carry out HVPE-GaN photoluminescence test analysis and its application research for improving the crystal quality of GaN,accelerating the industrialization process and developing test methods.This research takes a series of HVPE-GaN samples as the research object and focuses on the topic of photoluminescence test,analysis and application development.The main work of this paper is as follows:1?Based on the fundamental principle of photoluminescence,the methods for photoluminescence test and the spectral characteristics of different GaN samples are described through specific examples.The photoluminescence spectra of different GaN samples are collected and analyzed successfully,and the spectral database of HVPE-GaN samples is enriched and improved.2?The two-photon excited photoluminescence test system,which is commonly used in biomedical field in domestic area,is applied to the non-destructive characterization of the three-dimensional dislocation distribution of unintentionally doped GaN samples grown by HVPE.The three-dimensional dislocation distribution images of 200(X)×200(Y)×70(Z)?m~3 are successfully collected.To verify the validity of the test results,cathode fluorescence test is conducted,and the results suggest that the two-photon excited photoluminescence test is effective in characterizing the three-dimensional distribution of dislocation in GaN materials.3?Combining photoluminescence with secondary ion mass spectrometry measurements,the correlation between two luminescence lines,located at 23 me V and 16 me V below the excitonic emission line at 3.473 eV(4 K) respectively,and impurities in Ge doped GaN is studied.Combining photoluminescence with the Hall test,the correlation between photoluminescence spectra and carrier concentration in Ge doped GaN samples is analyzed from the perspective of energy band.The error between the experimentally measured carrier concentration and the carrier concentration calculated by using the formula between the full width of dominant photoluminescence band(?E) and carrier concentration(n),is less than one order of magnitude.These results indicate that photoluminescence measurementisafeasible method to characterize impurity and carrier concentration in Ge doped GaN materials.In this work,the indicators of dislocation,stress,impurity and carrier concentration in samples are characterized while the test and analysis of photoluminescence and its extended application are studied.This work not only reflects the crystal quality of HVPE-GaN,enriches the spectral database of HVPE-GaN,but also provides a reference for the development of new applications of traditional photoluminescence test.