It is not ear mites. That would be a dry crust and it would be in both of the ears. Not just one.
It sounds like a yeast infection but the only way to tell what is going on for sure is to have the vet take a sample out and look at it on the microscope. It could also be a bacterial infection and then the treatment would be antibiotics instead of antifungal/antiyeast treatment.
Hydrogen peroxide holds in moisture so it does not make a good ear cleaner. It is better to use an acidifying ear cleaner that has a drying agent in it. Yeast does not grow well in an acidic environment.
www.amazon.com/Malaseb-Flush-12oz/dp/B00061MOBG this is a good ear flush
To kill the yeast, or bacteria, it would be best to get a medication from your vet so you know if you are treating yeast or bacteria.
www.VeterinaryPartner.com/Content.plx?P=A&A=632 more on ear infections