Lateral Photovoltaic Effects And Resistive Switching Effects In Semiconductor Structures

The lateral photovoltaic effect and resistance switching effect are two promising effects in semiconductor nanomaterials.The lateral photovoltaic effect can be applied to high energy physics experiment,biomedical applications,process control,etc.The resistance switching effect is regarded as the next generation non-volatile memory due to its advantages in fabrication processes and outstanding device performance.In this paper,a variety of structures of Ni/n-Si,Ni/p-Si,Ag/ZnO/Pt/n-Si,Ag/TaO_x/Pt were prepared by magnetron sputtering.We studied the morphology,crystal structure,band structure,photoelectric properties,resistance change effect and so on by AFM,XPS,semiconductor integrated tester.Based on this,we studied the influence of surface states and Schottky barrier on lateral photovoltaic effect,and the ultal-low power resistive switching.The contents of this thesis are:?1?We observed a significant lateral photovoltaic effect on the surface of p-type Si induced by surface states,revealing a new mechanism for the generation of lateral photovoltaic effect.We studied the band structure of the samples using XPS.It revealed that the lateral photovoltaic effect on the p-Si surface was related to the surface band bending caused by the surface states.Finally,we validated our conjectures by changing the surface states of p-type silicon using Ni nano-films.?2?We observed an unexpected stronger LPE in Ni/SiO₂/p-Si than in Ni/SiO₂/n-Si.The largest sensitivity is increased more than 4 times.Furthermore,we investigated the transverse I-V curves and thickness-dependent position sensitivity characteristics.This enabled us to show the correlation between the Fermi level and the transportation of carriers.Finally,we proposed a model based on continuity and diffusion equations to explain the improvement in Ni/SiO₂/p-Si.?3?We observed a significant unipolar resistive effect on the Ag/ZnO/Pt/Si structure.We studied the effects of limiting current,ZnO thickness,partial pressure of oxygen and light field on the resistance change characteristics.Besides,we observed an ultra-low operating voltage bipolar resistive switching in Ag/TaO_x/Pt devices.Meanwhile,the bipolar resistive switching and threshold resistive switching in Ag/TaOx/Pt devices can be converted to each other by changing the magnitude of the I_CC.A simple but effective method is proposed in this letter to distinguish the two effects during the test.Finally,a model based on the migration of Ag+is proposed to explain the decrease of operating voltage and the conversion between bipolar and threshold resistive switching.These findings may lead to ultra-low power memories and contribute to a further understanding of the resistive switching effect.