Component doesn't use template

I want to extend Ember's textarea component. Therefore I created a file drop-files-textarea.js in app/components with this content:

import Ember from 'ember';

export default Ember.TextArea.extend({

// here comes the new behaviour
})

Now I'd like to add something to it's template. Therefore I created a file called drop-files-textarea.js in app/templates/components with this content:

{{yield}}
<p>added text</p>

This template is never used though. The Ember Inspector shows me that it uses the inline-template.

What am I doing wrong?