Cross-sectional view of nanowire geometries used in the model. Nominal parameter values are listed in Table I. (a) Core-shell nanowire with thin film deposition. (b) Core-shell geometry with p-doped shell and film absent from the base of the nanowire.
Model J-V characteristics for (a) top contact with sidewall passivation; (b) top contact without sidewall passivation using and ; and (c) sidewall contact with Fermi level pinning at midgap.
Electric potential plot at for (a) top contact with sidewall passivation and (c) sidewall contact. Dark lines delineate the top p-doped and bottom n-doped regions. Dashed lines delineate the substrate surface. Note the different vertical and horizontal spatial scales. Electric potential scale is in Volts. [(b) and (d)] Corresponding electric potential along the nanowire radius at a height of from (top curve) to 1 V (bottom curve) in 0.1 V increments. The curves for , 0.1 and 0.2 V overlap in (b).
Model J-V characteristics for top contact without passivation using and (a) (right-most solid curve); (b) (dashed curve); or (c) (dashed-dotted curve). Also shown are curves for with (d) ; (e) , identical to curve (b) of Fig. 2; or (f) . (g) and represents an upper limit in SRV and surface trap density for high performance solar cells.
Open circuit voltage, , vs nanowire diameter for (a) top contact with sidewall passivation; (b) top contact without sidewall passivation; and (c) sidewall contact. The diameters, and , have been normalized to the nominal values of 77 nm and 44 nm, respectively, as used in Fig. 2. and were changed concurrently by the same factor along the abscissa. Curve (b) was determined using and [as used for curve (f) of Fig. 4].
J-V characteristics for p-n structure with doping of (a) ; (b) , identical to curve (a) of Fig. 2; (c) ; (d) ; (e) and reduced shell height (dashed curve); and (f) and reduced shell height (dashed-dotted curve).
J-V characteristics for p-i-n structure with doping of (a) and (b) .
J-V characteristics under illumination (solid lines) and dark conditions (dashed lines) for (a) nanowire geometry of Figs. 1(a) or 1(b) with top contact and sidewall passivation; (b) nanowire geometry of Fig. 1(a) with top contact and without sidewall passivation; and (c) nanowire geometry of Fig. 1(b) with top contact and without sidewall passivation.
Nominal parameters used in the model.
Summary of solar cell performance.
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