Preparation Of Pure And Doping Zinc Nitride Films And Devices By Reactive RF Magnetron Sputtering

In the past few decades,research on ?-nitride semiconductors has led to outstanding optoelectronic device performance and commercial applications in lighting and power electronic devices.However,another class of nitride semiconductors,namely the ?3-N₂ materials,of which zinc nitride?Zn₃N₂?is an example,has received much less attention.The preparation of zinc nitride materials is inexpensive,and does not contain any toxic components.It has excellent electrical performance,such as high hall mobility and conductivity.As so far,the optical band gap of zinc nitride is uncertain.The variable optical band gap makes it possible for application in the field of optoelectronic devices.The optical band gap and excellent electrical properties could be obtained by doping zinc nitride.In this experiment,we fabricated pure zinc nitride,doped zinc nitride and devices by RF reactive magnetron sputtering.We used the method of pulsed laser deposition to prepare ZnCo₂O₄ as p-type layer of p-n heterojunction device and bottom-gate thin film transistor was fabricated.The effect of different preparation conditions and Al-doping on the properties of the films structure,composition,surface morphology and optoelectronic properties.This paper research and results are:1.A series of zinc nitride films were prepared on quartz substrate by RF reactive magnetron sputtering.The target material was pure zinc,N₂ was as reaction gas,Ar was as sputtering gas,growth temperature was 200?,the proportion of nitrogen and argon was 0%?100%,the chamber pressure was 3Pa?10Pa,the sputtering power was 60W?100W.The results of XRD showed the most of the zinc nitride films were polycrystalline with?321?preferred orientation.Large chamber pressure and small sputtering power reduced the energy of sputtering particle which affects the quality of thin films.Low proportion of nitrogen and argon could lead to not enough nitrogen to produce zinc nitride films.The growth condition of better crystalline quality of zinc nitride film was that:the growth temperature was 200?,the proportion of nitrogen and argon was 10:10,the chamber pressure was 7Pa and the sputtering power was 70W.2.A series of Al-doping zinc nitride films?ZnN:Al?were prepared on quartz substrate by RF reactive magnetron sputtering.By adjusting the cover area of the aluminum thin wafers,we fabricated thin films with different doping concentration.The growth temperature was 200?,the Al-doping proportion was 2%?10%,the proportion of nitrogen and argon was 20%?80%,the chamber pressure was 3Pa?10Pa,the sputtering power was 50W?100W.The results of XRD showed the most of the ZnN:Al films were polycrystalline with?321?preferred orientation.With the increase of the Al-doping proportion,the optical band gap of films increased,the images of SEM showed particles on the surface of ZnN:Al films were reduced and the grain boundary was more clear.The growth condition of better crystalline quality of zinc nitride film was that:the growth temperature was 200?,the proportion of nitrogen and argon was 6:14,the chamber pressure was 3Pa and the sputtering power was 70W.3.We used the method of pulsed laser deposition to prepare ZnCo2O4 as p-type layer and deposited ZnN:Al as n-type layer by RF reactive magnetron sputtering.Bottom-gate thin film transistor and p-n heterojunction device consisting of n-type ZnN:Al and p-type ZnCo₂O₄ were fabricated.The result of electrical test showed that the junction device had good rectification.In the visible range,the average transmittance of heterojunction device is above 30%.The thin film transistor showed saturation characteristic.