Selector elements that can be suitable for nonvolatile memory device applications are disclosed. The selector element can have low leakage currents at low voltages to reduce sneak current paths for non-selected devices, and higher leakage currents at higher voltages to minimize voltage drops during device switching. The selector element can be based on a silicon semiconductor layer doped with both carbon and nitrogen. The metal layer of the selector element can include conductive materials such as carbon, tungsten, titanium nitride, or combinations thereof.