Electronic transport for polymer/Si-nanowire arrays/n-type Si diodes with and without Si-nanowire surface passivation

The effect of Si-nanowire (SiNW) surface passivation on electronic transport of heterojunction diodes based on the poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonate) (PEDOT:PSS) and n-type Si with SiNW arrays was investigated in this study. The PEDOT:PSS/SiNWs/n-type Si diode without SiNW surface passivation shows a poor rectifying behavior with an ideality factor (eta) of 7.8 and high leakage. However, the PEDOT:PSS/SiNWs/n-type Si diode with SiNW surface passivation shows a good rectifying behavior with eta of 1.7 and low leakage. Such an improvement indicates that a good passivation is formed at the interface as a result of a combined effect of the formation of Si-O bonds and the removal of the short-lifetime charge traps. Note that SiNW surface passivation plays a significant role in the photoconduction by providing the contribution of long-lifetime charge trapping to the decay process. (c) 2013 Elsevier B.V. All rights reserved.