1. A method for forming a plurality of nonvolatile memory cells, the method comprising: forming a first plurality of substantially parallel, substantially coplanar first conductors; forming a first plurality of diodes above the first conductors; forming a first plurality of resistance-switching elements; and forming a second plurality of substantially parallel, substantially coplanar conductors above the first diodes, wherein the first resistance-switching elements comprise a material selected from the group consisting of Ni x O y , Nb x O y , Ti x O y , Hf x O y , Al x O y , Mg x O y , Co x O y , Cr x O y , V x O y , Zn x O y , Zr x O y , B x N y , and Al x N y .