Inserting space between the exponents and 10

I have a graph. The Y axis is plotted in the negative powers of 10 i.e. 10^-1, 10^-2, 10^-3, … .
I want to insert a space between 10 and -1.
Can anyone suggest how to do this??
Thank you.
Priyanka

You cannot change the axis labels look. They are obtained from numbers.