GaP monolithic display with low drive power

GaP monolithic numeric readouts with a character size of 3.1 mm × 2.2 mm have been developed by mesa-etching techniques. A serious spreading of the emitted red light beyond a segment, which is expected in GaP crystal because of low internal absorption, has been overcome by sufficiently deep mesa-etching with a combination of hot aqua regia and stable SiO2films. Completed devices with seven segments are operated at only 10 mA.