Diameter Scaling of the Optical Band Gap in Individual CdSe Nanowires

Abstract

The diameter dependence of the optical band gap of single CdSe nanowires (NWs) is investigated by a combination of atomic force microscopy, scanning fluorescence microscopy, and transmission electron microscopy. We find a good congruence of the experimental data to calculations within the effective mass approximation taking into account quantization, exciton Coulomb interaction, and dielectric mismatch. The experimental data are furthermore compared to different theoretical approaches. We discuss the influence of alternating wurtzite and zinc blende segments along the NWs on their optical properties.

Aqueous preparation of surfactant-free copper selenide nanowires

“…[27] In comparison with zero dimensional (0D) and bulk counterparts, one dimensional (1D) semiconductor nanostructures have many unique characteristics including asymmetric structure, intrinsic polarization anisotropies, long (macroscopic) length, band and/or ballistic transport etc. [28][29][30][31][32][33][34] The electrons in nanowires are quantum confined laterally and thus occupy energy levels that are different from the traditional continuum of energy levels or bands found in bulk analogues. 1D semiconductor nanostructures show great potential in fabrication of various optical and electronic nanodevices.…”

Structural control of photoconductive CdSe nanostructures through a Bi-assisted VLS process

“…4(d) represents the spectral response of the photodetector. The photocurrent showed maximum at ~600 nm, which corresponds to the band-edge emission of CdSe NWs (1.74 eV) [10]. This reveals that the photoconductivity was mainly due to the photo-generated charge carriers that were excited by the incident photons with energy larger than the band gap.…”

Power‐ and polarization dependence of two photon luminescence of single CdSe nanowires with tightly focused cylindrical vector beams of ultrashort laser pulses

“…c and f. For these experimental measurements a two‐photon excitation process must be taken into account, since the photon energy of the single laser pulse (800 nm, 1.55 eV) is smaller than the typical optical band gap (1.74 eV) for the CdSe NWs with diameters larger than 50 nm. Hence, a higher order of the intensity of the electric fields distribution needs to be considered to correlate the experimentally observed luminescence patterns.…”