Is it possible to create home screen app like widgets using sencha touch? (like the weather widget which stays on our mobile home screen)
Sencha Touch web apps should sit in a Web View regardless of where that is, so in theory that could be feasible. Unfortunately Web Views are not supported in App Widgets https://developer.android.com/guide/topics/appwidgets/index.html so there is no way obtaining that on Android at this time.
iOS is not going to support anything like widgets until iOS8.