Hi Ruchita,
The problem you are seeing is the way we deal with zero values on a logarithmic axis as logarithmic values tend to zero.
To get the chart to render nicely with a baseline of zero you need to replace your data values equaling 0 with 0.1.
Along with the current code you already have this should produce the chart you want.
I have notified our development team of this issue.
Let me know if you have any questions.
Kind regards,
Andrew Polkinghorn.