Memory cells comprising: a semiconductor substrate having a source region and a drain region disposed below a surface of the substrate and separated by a channel region; a tunnel dielectric structure disposed above the channel region, the tunnel dielectric structure comprising at least one layer having a hole-tunneling barrier height; a charge storage layer disposed above the tunnel dielectric structure; an insulating layer disposed above the charge storage layer; and a gate electrode disposed above the insulating layer are described along with arrays and methods of operation.