Electrochemical growth of Silicon nanostructures for photovoltaic applications

Silicon is the most widely used material for current photovoltaic (PV) panel manufacturing. Next generation solar cells will be obtained by creating novel device structures, material fabrication processes and implementing new physical principles. In this regard, semiconductor nanostructures have shown their potential for achieving efficient solar energy conversion at low cost due to their particular and tunable optical properties. Nevertheless, most of the fabrication techniques currently employed have some limiting factors, such as the need for high temperatures (T > 500 °C) or vacuum systems. For this reason in this work has been investigated the growth of Si nanostructures through the combination of a cost-effective technique like electrochemical deposition with the properties of liquid Ga as catalyst for the crystallization. Electrodeposition has been performed successfully on different substrates and for different temperatures and voltages. The results have been analyzed through SEM, EDX and XPS revealing a correlation between temperature/voltage and the oxidation state and homogeneity of the deposition. The actual effect of Ga in the process is not clear, but seems that under the current conditions is not really playing a role. Further experiments are planned to better understand the system and hopefully obtaining crystalline Si nanostructures exploiting the role of Ga as catalyst.