1. Introduction
The most attractive and abundant energy source to replace all
conventional energy resources is the sun. It is the largest single
source of energy for the earth. As a resource, more solar energy
reaches the earth in 1 h than all the energy consumed by mankind
in an entire year [1]. However harvesting the abundant solar energy
efficiently and in a cost effective way is still a challenge to the scientific
community. Solar energy is unique form of energy because
it is inexhaustible, free and plentiful enough to supply all personal
as well as industrial needs. This energy can effectively be utilized in
two ways, i.e., either by using it directly for heating of fluid (i.e. solar
thermal), or by converting it into electrical energy by using solar
photovoltaic (PV) modules. This energy has potential capability to
fulfillthe world’s electricitydemand withoutmuchnegative impact
on the environment. Solar radiation can be converted directly into
electricity with materials exhibiting a photovoltaic response. Semiconducting
materials can exhibit a photovoltaic response which
converts absorbed radiation into electric current [2]. Among the
various existing semiconductormaterials, siliconis themost widely
used semiconductor for the fabrication of solar cells [3]. At present,
the price of electricity generated from silicon solar cells is somewhat
higher than conventional energy sources. Hence there is a