A nonlinear diode which is easy to manufacture and has sharply nonlinear voltage-current characteristic and a matrix display unit in which it is used has a diode structure in which an amorphous semiconductor layer is disposed between a bus bar and a pixel electrode formed on a substrate so as to thereby provide an electrical connection therebetween. The amorphous semiconductor layer is made of a compound of arsenic and at least one of selenium and sulphur; a compound of nitrogen and at least one of boron; silicon; aluminium and gallium, a compound of carbon and silicon; or boron.