CUED Publications database

Direct observation of charge-carrier heating at WZ-ZB InP nanowire heterojunctions.

Yong, CK and Wong-Leung, J and Joyce, HJ and Lloyd-Hughes, J and Gao, Q and Tan, HH and Jagadish, C and Johnston, MB and Herz, LM (2013) Direct observation of charge-carrier heating at WZ-ZB InP nanowire heterojunctions. Nano Lett, 13. pp. 4280-4287.

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We have investigated the dynamics of hot charge carriers in InP nanowire ensembles containing a range of densities of zinc-blende inclusions along the otherwise wurtzite nanowires. From time-dependent photoluminescence spectra, we extract the temperature of the charge carriers as a function of time after nonresonant excitation. We find that charge-carrier temperature initially decreases rapidly with time in accordance with efficient heat transfer to lattice vibrations. However, cooling rates are subsequently slowed and are significantly lower for nanowires containing a higher density of stacking faults. We conclude that the transfer of charges across the type II interface is followed by release of additional energy to the lattice, which raises the phonon bath temperature above equilibrium and impedes the carrier cooling occurring through interaction with such phonons. These results demonstrate that type II heterointerfaces in semiconductor nanowires can sustain a hot charge-carrier distribution over an extended time period. In photovoltaic applications, such heterointerfaces may hence both reduce recombination rates and limit energy losses by allowing hot-carrier harvesting.

Item Type: Article
Divisions: Div B > Solid State Electronics and Nanoscale Science
Depositing User: Cron Job
Date Deposited: 17 Jul 2017 19:13
Last Modified: 19 Jun 2018 02:15