The invention provides a
Gunn diode with a Schottky-
ohm mixed
anode and a preparation method of the
Gunn diode. The
Gunn diode comprises a substrate, a buffer layer, a channel layer and a
barrier layer which are sequentially arranged from bottom to top. An
anode and a
cathode are respectively arranged on two sides of the top end of the buffer layer; a Schottky
anode is arranged at the top end of one side, close to the anode, of the
barrier layer; the
barrier layer is provided with a plurality of nanoscale grooves with gradually changing sizes and intervals. A Schottky contact and
ohmic contact mixed structure is adopted, when
metal with a high
work function makes contact with a
semiconductor, due to the difference between the work functions of the
metal and the
semiconductor, a Schottky junction is formed at an interface, and a
Schottky barrier with a certain height is formed; when the domain moves to the vicinity of the anode, the Schottky junction bears part of the
electric field, so that the
field intensity distribution near the anode is more uniform, the
peak intensity of the
electric field is reduced, and the
breakdown voltage of the device is improved.