Your problem is that Access won't support the superscript.
I assume you are speaking of, perhaps, Word or a similar product with its ability to set an attribute such as BOLD or superscript or subscript. But these are word-processing functions.
Access is NOT a word-processing program. It lacks the code within itself to do character attribute application (i.e. normal vs. bold vs. superscript.)
Having said that, I can offer some ways to cheat as long as you aren't talking about Datasheet view for tables or queries. For that, the answer is FLAT NO. But for forms or reports, there is hope for you.
Build the text representation of the field you wanted in scientific notation using the Format function. Then use the InStr function to locate the "E" and SPLIT the text apart.
Now on a Form or Report - make this into TWO text boxes. One of which is a smaller font than the other and raised above the level of the other. Then feed the mantissa to the normal, level text box. Feed the exponent to the small, elevated text box.
Yeah, I know. Ugly. But what can I tell you? Access ain't built to do this directly.
