The Achaemenid Empire generally used Aramaic for much of its history. This would've been written in Imperial Aramaic Script, which is related most closely to Hebrew script, but is related (sometimes closely, sometimes distantly) to other Semitic scripts.

edit: Here is what it looks like--it's on the bottom. Note that Imperial Aramaic was used between different parts of the far-flung empire--it was a standard language, not the language of the majority of people in Persia. And obviously, it wasn't even Persian.