Nano-optical emission of single colloidal CdSe nanowires
نویسنده
چکیده
We used near-field scanning optical microscopy (NSOM) having spatial resolution ∼100 nm in combination with diffraction-limited micro-photoluminescence (μ-PL) and time-resolved (TR) spectroscopy to study emission properties of single colloidal CdSe nanowires (NWs). Comparison of NSOM and wide-field μ-PL images allows observation of residual chemical and/or water drops attached to a NW, which act as a nano-lens providing efficient coupling of excited and emitted photons. At temperatures T < 150 K the emission spectra of a single NW reveal interference structure (period ∼λ/200) manifesting strong exciton-polariton coupling. Effects of carrier localization in wurtzite (W) and zinc-blende (ZB) sections of NW were observed in temperature dependent spectra. Type-I band alignment of ZB-W heterojunction was revealed from spectral dependence of emission decay.
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