How Does the Depletion Region in Semiconductors Function as a Capacitor?

[Rupa]

How the depletion region act as capacitor? My view is that there are no charges because if formed of recombination of charges. so, there is no charge... So, how can it act like a capacitor?
How the electric field is created in depletion region?
It's confusing me a lot ...

 

[grzz]

Is the poster talking about a p/n junction?

 

[Kholdstare]

There are ionized donors and acceptor atoms with their positive and negative charges respectively (called space charge - no carrier present, yet the region has charge), hanging in the lattice sites.