Finite-difference time-domain analysis of the tunability of Anderson localization of light in self-organized GaN nanowire arrays

Abstract

The possibility of tuning the resonance frequency and photon lifetime corresponding to Anderson localized resonant modes is investigated using the finite-difference time-domain technique. Experimentally obtained dimensions of molecular beam epitaxy grown self-organized nanowires on silicon have been employed to systematically generate disordered patterns, where multiple-scattering mediated light trapping has been analyzed. The results of our analysis indicate that in spite of the inherent randomness of the scattering medium, it is possible to control the wavelength and strength of the localized modes by varying dimensional features of the nanowires. The localization wavelength in the medium can be tuned toward a higher wavelength by increasing the average diameter of nanowires, whereas cavity quality factors in the order of 105 can be attained by increasing the fill factor of the array. The observed behavior is explained and empirically modeled, and the relation is found to be in good agreement with the predicted localization characteristics for experimentally grown self-assembled nanowires. The results of the analysis indicate that in spite of the absence of periodicity, localization in this medium is related to interference effects resulting from Bragg-like diffractions, which in effect results in the observed systematic variation of localization characteristics as nanowire dimensions are varied.

III-Nitride Light-Emitting Devices

“…In addition to these, low-dimensional systems in the form of quantum dots, disks, and wells can be conveniently incorporated in the active region of nitride nanowires to attain strong carrier confinement. From the photonic point of view, strong optical confinement-even in the form of Anderson localization-can be attained in III-nitride nanowires, and such confined modes can be conveniently tuned by controlling geometrical aspects of these nanostructures [222,272]. The mentioned exotic electrical and optical properties have encouraged the experimental realization of numerous LEDs and electrically pumped lasers based on III-nitride nanowires.…”

Disorder induced absorption enhancement of light in GaAs nanowire array

“…The height of the NWs can be controlled by tuning the etch parameters during the processing and fabrication process. Though the random array of NWs can also be experimentally realized by EBL or nanoimprinting techniques-provided the mask or mold itself constitutes a random pattern-a more established approach would be to utilize self-organized epitaxial techniques like molecular beam epitaxy or metal-organic chemical vapor deposition [4,23]. These techniques have been consistently utilized to grow and fabricate self-organized, random NW array based photonic and optoelectronic devices like LEDs, lasers, photodetectors etc [24,25].…”

“…propagation [1,2] and Anderson localization of light in disordered medium [3,4], directionality control of whispering gallery resonators [5], tunability of photonic bandgaps [6], light harvesting in solar cells [7], and light absorbers [8] etc. Among such multifarious studies, disordered surfaces and disordered nanowire (NW) arrays have received considerable attention due to their potential applications in enhancing light trapping in photovoltaic cells [8][9][10].…”