Carrier recombination efficiency and photocarrier transport in vertically aligned silicon nanowire arrays as probed by photoluminescence and terahertz spectroscopy

College

College of Science

Department/Unit

Physics

Document Type

Dissertation

Publication Date

6-2016

Abstract

Terahertz (THz) emission and photoluminescence (PL) spectroscopy were utilized to study the carrier dynamics and recombination characteristics of vertically align silicon nanowire synthesized by metal-assisted electroless etching, respec­tively. It is observed that the carrier dynamics is greatly affected by the presence of pores on the nanowire walls in two-step synthesized silicon nanowires compared to nanowire synthesized using a one-step process. The carriers are collected in these pores, acting as defect sites for efficient carrier r combination upon photoexcitation as shown by the temperature-dependent PL. Th pores also effectively weaken the surface electric field; thereby, deterring the mission of THz radiation. Lastly, the dependence of the THz emission on nanowire length is seen only for the nanowires synthesized by a one-stop process· while the PL intensity of the nanowire samples synthesized by the two-step process exhibited a dependence on nanowire length.

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Disciplines

Physics

Keywords

Nanowires; Nanosilicon

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