A thermal inkjet printhead includes unpassivated heater resistors whose resistive material is doped, preferably with oxygen, nitrogen or an equivalent dopant, for increasing the resistance of the material. By increasing the resistance of the resistive material through doping, the drive currents for generating heat within the resistors need not be changed from levels which inkjet printers are presently designed to work with. The printhead of the invention can thus be used in place of a standard printhead without modification to the printer.