What are the ideal materials for the fabrication of a solar cell? Give the criteria for their selection.

(N/A) Semiconductors with a band gap close to $1.5 \text{ eV}$ are ideal materials for solar cell fabrication.
These materials include:
$Si$ $(E_{g} = 1.1 \text{ eV})$,
$GaAs$ $(E_{g} = 1.43 \text{ eV})$,
$CdTe$ $(E_{g} = 1.45 \text{ eV})$,
$CuInSe_{2}$ $(E_{g} = 1.04 \text{ eV})$,etc.
The following are the important criteria for selecting the right materials for fabricating a solar cell:
$(1)$ Band gap $E_{g}$ should be in the range of $1.0 \text{ eV}$ to $1.8 \text{ eV}$.
$(2)$ High optical absorption,approximately $10^{4} \text{ cm}^{-1}$.
$(3)$ High electrical conductivity.
$(4)$ The raw material should be easily available.
$(5)$ The cost of the material should be low.