Direct observation of charge-carrier heating at WZ-ZB InP nanowire heterojunctions
Journal
Nano letters
Journal Volume
13
Journal Issue
9
Pages
4280
Date Issued
2013-09-11
Author(s)
Wong-Leung, Jennifer
Joyce, Hannah J
Lloyd-Hughes, James
Gao, Qiang
Tan, H Hoe
Jagadish, Chennupati
Johnston, Michael B
Herz, Laura M
Abstract
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.
Subjects
Nanowires; hot carriers; type II heterojunctions; stacking faults; photovoltaics; ELECTRON-HOLE PLASMAS; DYNAMICS; PHOTOLUMINESCENCE; EFFICIENCY; TRANSPORT; EXCITONS
SDGs
Publisher
AMER CHEMICAL SOC
Type
journal article