Semiconductor nanowires (NWs) are of strong interest because of their unique properties including good charge transport along the long axis, which is important for many potential applications including solar energy conversion. It is important to understand the exciton dynamics in semiconductor NWs and their relation to charge carrier properties and device performance in solar electricity or solar fuel generation. Ultrafast laser techniques are ideally suited for probing exciton and charge carrier dynamics on various time scales. For example, we have applied transient absorption (TA) spectroscopy to study the exciton dynamics in two important semiconductor NW structures, silicon NWs and InGaN/GaN quantum well (QW) NWs. For the second system, the effect of Rh/Cr<sub>2</sub>O<sub>3</sub> catalyst is also investigated, which was found to lead to longer average charge carrier lifetime. Kinetic models are developed to explain the key dynamic features and gain deeper insight into exciton/charge carrier relaxation pathways of these semiconductor NWs. Implications of the dynamics results in solar energy conversion applications are discussed.

Ultrafast exciton dynamics in semiconductor nanowires and implications in solar energy conversion

250th National Meeting (2015)

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