The resistive switching behavior of CdZnTe film was reported by our group, but the reason for resistive switching behavior is still obscured. The top electrode (TE) has a great effect on resistive switching behaviors, especially on the generation of the resistive switching, the ON/OFF ratio, the retention time and the voltage parameter distribution. This could be explained by different conduction mechanisms in RRAM including phase change effect (PCM), electrochemical metallization effect (ECM), valence change effect (VCM) and polarization-induced charge transfer. TE/CdZnTe/Pt/Ti/SiO2/Si structures (top electrode TE = Au, Pt, Al, Ti and Cu) were fabricated by magnetron sputtering and thermal evaporation. Bipolar resistive switching behavior was observed in TE/CdZnTe/Pt/Ti/SiO2/Si structure when TE is Al, Ti or Cu, but Pt or Au as TE in TE/CdZnTe/Pt device showed no resistive switching. The interfacial layer (AlOx, TiOx, CuOx)-dominated model was proposed to explain the presence of resistive switching behavior in TE/CdZnTe/Pt device due to oxidizable electrodes. The role of the CdZnTe film is a series resistor after the forming process. Space charge-limited current (SCLC) model was used to analyze the conduction mechanism and ~1019 cm-3 trap density in the interfacial layer was calculated by fitting the current-voltage curve. The device properties including voltage parameter distribution, retention property and endurance property were tested, respectively. The Al/CdZnTe/Pt/Ti/SiO2/Si structure has a good potential as resistive switching random access memory with over 103 ON/OFF ratio and at least 103s retention time. The comparison including switching type, switching mechanism, cycling numbers, retention time and ON/OFF ratio for different chalcogenide materials as resistive switching layer.
Aoqiu Wang received bachelor degree in the major of material science and engineering from Northwestern Polytechnical University in 2014. She started to the research on CdZnTe film from year 2015 as a master. In year 2016, she became a doctor and her research interest extends to chalcogenides film, especially, the potential of chalcogenides material in RRAM fields. Now, she has investigated the resistive switching mechanism of CdZnTe, ZnSe, ZnTe and ZnS materials. The related publications are under arrangement.
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