Self-organization Growth Behavior Study Of GaN And ZnO And Its Device Application

The self-organization growth behavior of Ga N and Zn O were stided based on a more general self-organization theory.Some of the contraditions about the Ga N growth mechanism solved,and the nature of self-organization growth of Zn O nanowires were understood.The proposed model was applied it to improve the performance of UV sensor and to develop the new device structure.The main results are as follows:1According to the classical thermodynamic theory,the surface pits of Ga N are1? According to the classical thermodynamic theory,the surface pits of GaN are formed by screw dislocations,but the size of the pits predicted by the theory is much smaller than that observed in the experiments.According to the local equilibrium assumption of dissipative structure,the closer to equilibrium the system is,the larger the range of the local equilibrium state is,the smaller the surface pit is.If the system begins to deviates from the equilibrium state,the range of equilibrium state relative to the screw dislocation spiral center and the edge is too small,the two can not be in the same equilibrium state,when the dislocation core reaches the critical value of 1/r0,accelerate the rate of curvature at center is not zero,so the pit will continue to expand to form a large one.When the system is far from equilibrium,the Ga N nanowire arrays will be formed.2? With GaN as the base material,only the orientation is different,the c-plane GaN pits are considered to be formed by the screw dislocations,while the a-plane Ga N pits are considered to be formed by the merging of the islands.However,we found that pits on a-plane Ga N are formed by screw dislocation,not only that,the surface pit formed by complete screw dislocation is larger than that formed by incomplete dislocation with screw component form.Therefore,the formation mechanism of the a-plane and c-plane is same.3? Based on the observation of the evolution process,we found the self-origanization rule depicted by synergetics.Resource competition is the nature of Zn O nanowire ordered structure.The large nucleation has a competitive advantage,resulting in growth,and small nucleation disappear or less.So,the large nucleus is the order parameter;then,order parameter slaves reactive atoms to repeate its model,this process is the servo mechanism.The change of concentration makes clear the emergence and disappearance of the competition of resources.If there is no competition,thus,there is no order parameter,nonlinear interaction and ordered structure.The relationship between them is interlocking and indispensable.4? Based on the synergetic principle of self-organization growth of Zn O nanowires,we have realized the customizable gain of the nanowire array UV detector.By adjusting the matching between the electrode,the thickness of the seed layer,the growth concentration and the growth time,the morphology of the grown nanowires is regular and achieve the nanowires bridging ultraviolet detection device.In the final analysis,the key to get the customizable gain of the nanowire array UV detector is to find the suitable solution concentration under a given condition,so that the growth is always in the state of resource competition.5? By comparing the growth of Zn O nanowires on different orientations Ga N substrate,we found that the polarity is necessary condition of Zn O nanowires;The defects on the surface provide nucleation sites for self-organization growth;meanwhile,the surface fluctuation also greatly affect the density and orientation of nanowires.Accordingly to it,we propose a semipolar Alx Ga1-x N/Ga N heterojunction HEMT ultraviolet detector with oblique Zn O nanowires grown on the gate,and the sensitivity and response speed of the detector can be improved by the modulation of 2DEG by UV light.