Abstract
A double-gyroid nanostructure is a two-component heterostructure that is three-dimensionally periodic, with one material forming a continuous wall-like region of nearly constant thickness centered on the zero-mean curvature $G$ surface. The other material forms two individually continuous channel-like regions. Semiconductor nanostructures with this topology may now be fabricated, and we present here the first calculation of the electronic structure of such materials. We use the simplest two-band envelope function method that can yield information on the nature of quantum confinement effects. We report the density of states and wave functions for the case of PbSe and show that when PbSe fills the channel-like region, the resulting double-gyroid PbSe nanowire network displays quantum confinement effects with a blueshifted band gap of 0.50 eV (1.77 times the bulk PbSe band gap of 0.28 eV). In addition, the low-energy density of states (DOS) contains a series of peaks separated by gaps; we attribute the enhancement of the DOS in the peaks to a weak dependence of energy on the quasimomentum. Thus, we suggest that these structures may have some similarity with zero-dimensional or one-dimensional materials in regard to their photophysics, yet may have more similarity to three-dimensional materials with regard to their transport properties. As a result, they may be of aid in harnessing nonlinear optical effects, such as carrier multiplication phenomena, for high-efficiency photovoltaic or photoelectrochemical devices.
Published Version
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