This is a result of Schottky barrier formation at the junction of Al and SiNWs. The formation of the Schottky barrier between the SiNWs and Al has been reported previously

and is due to the large difference in work functions of these materials [16–19]. It is also observed from Figure 8 that the threshold voltage is very high, and the typical value is around 6 V (± 0.4 V). It is assumed that the electric current in Schottky contact is because of thermionic emission. The ideality factor (n) was estimated using the current–voltage relationship I = I sexp (eV/nkT) for the Schottky diode, where I s is the reverse saturation current, V is the applied voltage, k is Boltzmann constant and T is the temperature in Kelvin. Ideality factor is extracted from the slope of the linear region in forward bias, and I s is obtained by extrapolating the intercept find more with axis where voltage is zero from ln(I) vs. V plot. Values of n and I s are obtained to be 17.68 and 91.82 pA, respectively. the high value of ideality factor may be attributed

to the presence of MLN0128 native oxide on electrodes and non-homogenous barrier [20, 21]. Some more possible reasons could be space-charge limited conduction, parasitic rectifying junctions within the device [22] and the presence of large number of surface states [23]. Further investigation is underway to unfurl this experimental observation. Figure 8 I – V characteristics of the Schottky diode with SiNWs. Solar cell characteristics MM-102 The schematic structure of the Schottky solar cells with the Al/SiNWs/TCO/glass structure can be seen in Figure 9. Fabricated solar cell showed photoconductivity and photovoltaic characteristics. The I-V characteristics of

the fabricated Dichloromethane dehalogenase solar cell are shown in Figure 10. Open-circuit voltage (V oc) and short-circuit current (I sc) are measured to be 0.204 V and 70 nA, respectively, with fill factor of 0.23. The small fill factor and efficiency could be due to some parasitic resistances which actually reduce the squareness of the curve in the fourth quadrant. Figure 9 Schematic structure of the Al/SiNWs/TCO/glass solar cell. Figure 10 Illuminated I – V characteristics of fabricated Schottky solar cell depicting V oc and I sc . The curve in the bottom right quadrant is flat, which indicates high sheet and low shunt resistances. Shunt resistance is generally caused by leakage current which arises from pinholes and recombination traps in the active layer [24]. It is reported that the leakage can also occur due to the shunting of surface leakage along with junction leakage [24]. It has been reported that silicon structures grown by PECVD process usually contain bonding defects, interstitial atomic and molecular hydrogen, some voids which actually affect the activity of photo-generation of carriers [25]. Interestingly, the stability of the V oc with time shows negligible change (Figure 11).