Scattering attributes of one-dimensional semiconducting oxide nanomaterials individually probed for varying light-matter interaction angles

Abstract

We report the characteristic optical responses of one-dimensional semiconducting oxide nanomaterials by examining the individual nanorods (NRs) of ZnO, SnO 2 , indium tin oxide, and zinc tin oxide under precisely controlled, light-matter interaction geometry. Scattering signals from a large set of NRs of the different types are evaluated spatially along the NR length while varying the NR tilt angle, incident light polarization, and analyzer rotation. Subsequently, we identify materialindiscriminate, NR tilt angle-and incident polarization-dependent scattering behaviors exhibiting continuous, intermittent, and discrete responses. The insight gained from this study can advance our fundamental understanding of the optical behaviors of the technologically useful nanomaterials and, at the same time, promote the development of highly miniaturized, photonic and bio-optical devices utilizing the spatially controllable, optical responses of the individual semiconducting oxide NRs. [16][17][18][19][20][21][22][23][24] In many of these technologically important applications, the fundamental optical properties of 1D SO nanomaterials govern their functional outcomes. Light can produce various optical and optoelectronic responses from the materials and, therefore, light-matter interactions can be engineered to produce desirable optical properties such as spontaneous and stimulated emission, 1,25-29 waveguiding, 1-3 and evanescence field enhancement. 4,[30][31][32] Such examples can be seen in the research efforts previously reported for the development of SO nanomaterials for applications in nanoscale lasers, 25,26,29 subwavelength waveguides, 1-3,33,34 and biodetection platforms. 17,18,20,23,24,33,35 Specifically, nanomaterials of zinc oxide (ZnO), tin oxide (SnO 2 ), indium tin oxide (ITO), and zinc tin oxide (ZTO) have been widely utilized as signal transduction elements in optical detection devices. 5,8,36,37 These past applications have primarily exploited the optical properties of bulk materials or ensembles of nanomaterials. With the ever-growing demand for device and sensor miniaturization, novel constructs with highly reduced dimensions have also been explored recently. Therefore, elucidating the exact light interaction profiles with individual nanostructures can provide much needed insight and further benefit the burgeoning efforts in single nanorod (NR) optical, optoelectronic, and biosensing devices.In this study, we carry out dark-field (DF) experiments in a forward scattering geometry and investigate the fundamental optical responses of individual nanomaterials by systematically controlling the interaction angle between the direction of an incident light oscillation and the main crystal axis of a nanomaterial. 1D nanomaterials, specifically NR forms of ZnO, SnO 2 , ITO, and ZTO are examined for their interaction angle-dependent, elastic scattering profiles. We determine characteristic scattering responses from each position along the main axis of the SO NRs while controlling the NR orientation, incident light p...

Evaluation of polarization rotation in the scattering responses from individual semiconducting oxide nanorods

“…The 3-dimensional (3D) contour plots simultaneously chart the scattering intensity, the position along the NR long axis, and the analyzer angle under the different incident light settings controlled by the wavelength and the polarization direction of the incoming laser. As reported earlier, the scattering response from individual NRs can either be continuous or discontinuous, depending on the NR tilt angle 15 . With the θ of 70 o , the FDF scattering patterns from the ZnO NR are expected to be discontinuous, as shown in Figure 2, due to the dominant component of E ⊥ projected onto the sample plane, mimicking the highly localized scattering signal discretely monitored only at the two NR ends at high θ angles approaching 90 o 15 …”

“…As reported earlier, the scattering response from individual NRs can either be continuous or discontinuous, depending on the NR tilt angle 15 . With the θ of 70 o , the FDF scattering patterns from the ZnO NR are expected to be discontinuous, as shown in Figure 2, due to the dominant component of E ⊥ projected onto the sample plane, mimicking the highly localized scattering signal discretely monitored only at the two NR ends at high θ angles approaching 90 o 15 …”

“…In general, we also observe that the angle shift in the polarization oscillation of the scattered light becomes larger as the NR tilt angle of θ increases. And the polarization rotation effect in the scattered light occurs more pronouncedly on the ZnO NRs of the intermittent and discrete scattering nature 15 relative to the continuous type.…”

Position- and Polarization-Specific Waveguiding of Multi-Emissions in Single ZnO Nanorods

“…8,9,10,11,13,14,15,16,17 In this regard, highly efficient excitonic photoluminescence (PL) has been reported for its spontaneous and stimulated emission applications. 4,7,18,19,20 In addition, we have previously identified distinctive Mie and Raman scattering characteristics of intrinsic ZnO NRs 21,22 as well as fluorescence emission properties from fluorophores placed in the vicinity of ZnO NRs. 15,16,17…”

“…Unique optical properties of zinc oxide (ZnO) nanomaterials afford many important optoelectronic and biomedical applications for which nanoscale ZnO materials have been previously constructed into highly miniaturized light-emitting diodes, − lasers, − waveguides, − and biosensors. − Burgeoning research efforts have made for the discovery and engineering of novel optical properties of ZnO, particularly one-dimensional (1D) ZnO nanomaterials, such as nanorods (NRs) and nanowires (NWs). 1D ZnO nanomaterials have proven attractive as their inherently high shape anisotropy and reduced dimensionality can be exploited to further enhance the materials’ unique optical properties, such as extremely directional light propagation/emission and highly localized light delivery/collection. − ,− In this regard, highly efficient excitonic photoluminescence (PL) has been reported for its spontaneous and stimulated emission applications. ,,− In addition, we have previously identified distinctive Mie and Raman scattering characteristics of intrinsic ZnO NRs, , as well as fluorescence emission properties from fluorophores placed in the vicinity of ZnO NRs. − …”