Synthesis Of Beryllium And Nitrogen Co-doped ZnO Nanowire Arrays And For The Application Of Light Emitting Diode

People's requirements for light sources have become higher,and more efficient,environmentally friendly and safe light source devices have become the research direction of experts and scholars with the rapid development of society.Zinc oxide(ZnO)is a semiconductor material with a wide band gap of 3.37 e V.It has a very high exciton binding energy(60 me V),which is much greater than the thermal ionization energy at room temperature(25 me V),and ZnO is a transparent oxide,non-toxic,environmentally friendly,and abundant in reserves.It lays the foundation for the realization of efficient,stable and safe ZnO-based short-wavelength optoelectronic devices.However,due to the self-compensation effect of oxygen vacancies in ZnO materials,more defect states and lower solubility of acceptor dopants,it is difficult to obtain efficient p-type doping of ZnO,which severely limits the research progress of ZnO-based optoelectronic devices.In order to solve this problem,experts and scholars have done a lot of research work for this.In this paper,the method of co-doping of Be andN double elements is used to solve the problem of p-type doping of ZnO,and to construct a heterojunction LED device,explore its photoelectric performance,and explain the light-emitting mechanism.The research content of this paper is as follows:1.Be-N co-doped ZnO nanowire arrays were grown by chemical vapor deposition(CVD)with n-type GaN as the substrate.using XRD and SEM and other characterization techniques to test the phase and morphology of the nanowires.The results show that the ZnO nanowire array is dense and neat,with a diameter of 100-150 nm and a length of about 4.7 ?m,which is a standard zinc oxide wurtzite structure.Nanowires have good crystallinity and grow along the(002)crystal plane.2.Growing Be-N co-doped ZnO nanowire arrays on p-type silicon wafers,the molar composition of Be O in the raw materials is 10%,which constitutes a field effect tube(FET)structure,and the output characteristic curve is tested to prove the conductivity type of ZnO nanowires is p-type,and the Hall effect is used to test the conductivity type,carrier concentration,electron mobility,resistivity,etc.of ZnO nanowires,which realizes the effective p-type doping of ZnO.There are characteristic peaks of Be andN elements in the XPS spectrum,and the element content is 6.57% and 0.82%,respectively,which is relatively low,which also shows that it is a trace doping.3.Fabricate p-ZnO:(BeN)/n-GaN heterojunction LED devices,apply forward bias to the device,and when the threshold voltage reaches 12 V,the device emits red-orange light with a peak at 617 nm,gradually increasing at high voltage,the luminescence peak of the device shifts to the short-wavelength direction at 18 V,the luminescence peak is located at 429 nm,showing high-intensity blue emission,the blue shift is about 200 nm,and the luminescence intensity is also increased by 10 times.The emission of red-orange light is mainly caused by the transition of electrons in the conduction band to the defect energy level.The shift of the peak position is mainly due to the injection of large currents,which increases the energy obtained by the carriers and reduces the interface barrier.It is easier for electrons to pass through the interface to form interface radiation recombination,causing blue light emission.4.Control the composition of Be O in the raw material,and adjust the double elements' doping concentration of Be andN in the ZnO lattice.The ratio of Be O in the raw material to ZnO is 2%,5%,15% and 20% mol,respectively,to construct p-ZnO:(BeN)/n-GaN heterojunction devices.The LED device with 2% mol doping concentration transitions from low-bias red light to high-bias blue light emission,realizing high-brightness red?green and blue color light emission,and bright blue light can still be observed under normal lighting conditions;LED devices with 5% mol doping concentration achieve red-orange light emission;when LED devices with 15% mol doping concentration continue to increase the forward bias voltage,near-band-edge emission gradually dominates,finally achieving near-ultraviolet light emission;under high current injection of a heterojunction device with a doping concentration of 20% mol,stimulated radiation dominates,and a large number of high-energy state particles are reversed,resulting in 697.24 nm Laser.All concentrations heterojunction devices have varying degrees of lasing behavior near 697 nm,and with the increase of doping concentration,the lasing peak gradually dominates.In this paper,Be-N co-doped ZnO nanowire array was grown on an n-type GaN substrate by CVD method,and a total of five p-ZnO:(BeN)/n-GaN heterojunction devices with five doping concentrations were fabricated.Not only realized the high-intensity blue light emission at 429 nm,but also the near ultraviolet light emission at 403 nm and the laser emission at 697.24 nm,and also realized the high-brightness light emission of the three primary colors of red,green and blue from a single device,which is the best of ZnO-based optoelectronic devices.Development has laid the foundation.