Research On New Type Cadmium-based Semiconductors: Nanostructure Synthesis And Photoelectric Properties

Cadmium based materials such as CdS，CdSe and CdTe, the typical II-VI groupsemiconductors, which have been proved to own great optical and electrical properties.They play an important role in lots of hot research area, especially in photoelectricconversion device. Among which, the synthesis and the application of cadmium basedmaterials in nanoscale just be the hottest. But up to now, the bottleneck emerge thatbe lack of structural diversity, limited synthesis methods and slow in performanceimprovement. Well it’s belived the basic solution for this bottleneck is the effectivecombination of the research of both materials synthesis and application, to designstructure based on the requirement of its application.In this paper, some preliminaryexploration and research has been carried out based on the requirements of cadmiumbased materials’ photovoltaic application,and the structure design of the devices,newly materials synthesis methods and actual application performance would befocused. The main research results are as follows.1. Three-dimensional porous CdS QDs structure with controlled pore size andphotoanode thickness was fabricated based on PS templates with a vacuumself-assembly process. The optimal thickness and annealing temperature of the porousstructure is obtained. The post CdS electrodeposition was applied to improve thecontact between quantum dots and enhance carrier transportation. And the post CdSeelectrodeposition was applied to improve the charge separation by built-in electricfield between CdS/CdSe, a high photoelectric conversion efficiency of2.47%wasobtained.2. CdTe nanoflake arrays were fabricated directly on conductive substrate viagas-phase tellurization of cadmium nanoflake template. A put-in-heating techniquewas developed to prevent the fusion and collapse of cadmium template, as a result, thenanoflake morphology was well preserved during high temperature tellurization. Asimple photoresponse device based on CdTe nanoflake arrays was assembled andexhibited high performance (880%), indicating that CdTe nanoflake arrays arepromising for photoelectrical application.3. The CdSe sensitized film was electrodeposition(ED) onto the ZnO/CdSnanowire substrate to explore the influence of ED parameters on the QDSCs’ performance. The product phase, coating rate and partial size be effected by EDpotential were researched, and the other key parameters like Cd2+/Se2-source ratio,reaction time were optimized. The optimalizing parameters and the inner affectionwere obtained, led to a high photoelectric conversion efficiency of2.09%.