An Analytic Approach for Optimal Geometrical Design of GaAs Nanowires for Maximal Light Harvesting in Photovoltaic Cells

Abstract

Semiconductor nanowires(NWs) with subwavelength scale diameters have demonstrated superior light trapping features, which unravel a new pathway for low cost and high efficiency future generation solar cells. Unlike other published work, a fully analytic design is for the first time proposed for optimal geometrical parameters of vertically-aligned GaAs NW arrays for maximal energy harvesting. Using photocurrent density as the light absorbing evaluation standard, 2 μm length NW arrays whose multiple diameters and periodicity are quantitatively identified achieving the maximal value of 29.88 mA/cm2 under solar illumination. It also turns out that our method has wide suitability for single, double and four different diameters of NW arrays for highest photon energy harvesting. To validate this analytical method, intensive numerical three-dimensional finite-difference time-domain simulations of the NWs’ light harvesting are also carried out. Compared with the simulation results, the predicted maximal photocurrent densities lie within 1.5% tolerance for all cases. Along with the high accuracy, through directly disclosing the exact geometrical dimensions of NW arrays, this method provides an effective and efficient route for high performance photovoltaic design.

Synthesis and Applications of III–V Nanowires

“…Next we will address each of these topics. We have also identified an impressive amount of papers dealing with optical and electrical simulations of NW solar cell arrays, − ,− but this topic is beyond the scope of this section.…”

Analysis and design of InAs nanowire array based ultra broadband perfect absorber

“…Short circuit current density, LAE and EF for different optimized InAs NW based structures are summarized in Table 2 . The highest short circuit current density for normal incidence is found to be 39.08 mA cm −2 for quad radii InAs NW structure which is significantly higher than GaAs NW 17 and InP NW 43 based structure. If the quad radii InAs NW structure is illuminated at 10° angle of incidence, the short circuit current density value soars even higher at 40.15 mA cm −2 accounting for ∼95% conversion efficiency comparing with the AM 1.5 spectrum 51 (∼42 mA cm −2 ).…”

Efficient wave optics modeling of nanowire solar cells using rigorous coupled-wave analysis

“…The optimal nanowire solar cell arrays consists of nanowires that are a few microns in height and with diameters and periodicities comparable to the wavelengths present in the solar spectrum [1,2]. These small sizes require full wave optics simulations to accurately model their optical properties, unlike in standard planar devices [3,4].…”

“…There is a need for fast, accurate modeling tools to enable rapid exploration and optimization of nanowire designs. Conventionally, finite element [4,[9][10][11] and finite difference methods [1,12,13] have been used in optical models of NWSC. While these techniques are highly accurate, they are computationally expensive, limiting their usefulness in a closed-loop global device optimization.…”