Research progress of silicon nanowires array photodetectors

Abstract

As one of the most important semiconductor materials, silicon (Si) is widely used in optoelectronic devices such as solar cells and photodetectors, and so on. Due to the refractive index difference between silicon and air, a large amount of incident light is reflected back into the air on the silicon surface. In order to suppress the loss caused by this reflection, a variety of silicon nanostructures with strong trapping effect have been developed. Most of the dry-etching schemes have the problems of high cost and complex preparation, while the silicon nanowire arrays prepared by the wet-etching schemes have the problems of low controllability of some parameters such as the spacing between each nanowires, and the small effective area of heterojunction, and so on. The method by using polystyrene microsphere as the mask can combine the advantages of dry-etching and wetetching methods, and it is easy to obtain periodic silicon nanowires (pillars) array. In this paper, firstly we summarize the properties and preparation methods for silicon nanowires structure, the strategies to effectively improve the performance of silicon nanowires (pillars) array photodetectors, and then to analyze the existing problems. Further, the latest development of silicon nanowires (pillars) array photodetector is discussed, and then the structure, morphology of photosensitive layer and methods to improve the performance parameters of silicon nanowires (pillars) array photodetector are analyzed. Among them, the ultraviolet light sensitive silicon based photodetector and its method to show tunable and selective resonance absorption through leaky mode resonance, the silicon nanowires array photodetector modified with metal nanoparticles and the method of improving performance through surface plasmon effect and plasmon hot electrons, are focused. Heterojunction photodetectors composed of various low dimensional materials and silicon nanowires (pillars) array, and methods to improve the collection efficiency of photogenerated charge carriers through the "core/shell" structure, methods to expand the detection band range of silicon-based photodetectors by integrating down-conversion lightemitting materials and silicon nanowires (pillars) array, flexible silicon nanowires array photodetectors and their various preparation methods, are all introduced. Then, the main problem that a large number of defect states will be generated on the silicon nanostructure surface during the MACE process is briefly introduced, and several possible solutions for passivation are also presented. Finally, the future development of silicon nanowires (pillars) array photodetectors is prospected.

RNA-Seq Transcriptome Analysis and Evolution of OsEBS, a Gene Involved in Enhanced Spikelet Number per Panicle in Rice

“…Further, the ratio of CTK/IAA has an important effect on organ differentiation. A high ratio of CTK/IAA during rice spikelet differentiation was conducive to promoting panicle differentiation and inhibiting spikelet degeneration [ 18 , 19 ]. For example, over-expression of auxin signal transduction factor OsAFB6 caused a significant decrease in the IAA level and increase in the CTK level, leading to larger spike shapes [ 21 ].…”

“…There is also a significant association between spikelet development and CTK content in rice. High concentrations of CTK/indole-3-acetic acid (IAA) are beneficial for prolonging the differentiation period and promoting spikelet differentiation during spikelet development [ 18 , 19 , 20 ]. Over-expression of rice Auxin-signaling F -Box 6 ( OsAFB6 ), the gene that encodes an auxin signal transduction factor, causes a significant decrease in IAA level and a significant increase in the biological activity level of CTK, leading to a larger spike [ 21 ].…”