line c c in fig3 a a cross sectional view taken along the line b b in fig3 a is the same as that in the second embodiment shown in fig2 on the other hand since a construction of the semiconductor electron emitting device is similar to that of the second embodiment its detailed descriptions are omitted as shown in fig3 a and 3b p layers 4a to 4h schottky electrodes 5a to 5h and the device separating regions 12b are individually formed in and on the semiinsulative gaas 100 substrate 12a by the ion implantation process in the above construction a number of semiconductor electron emitting devices as shown by 4a to 4h are formed in a line in the electron emitting portions by individually applying the reverse biases to a number of electrodes as indicated by 5a to 5h each electron source can be independently controlled as described above in detail according to the semiconductor electron emitting devices of the embodiments the schottky diode is formed by joining the schottky electrode to the p type semiconductor and the junction of the diode is reversely biased thus the vacuum level e vac can be set to an energy level lower than the conduction band e c of the p type semiconductor an energy difference u03b4e larger than that in the conventional device can be easily obtained further by causing the avalanche amplification a number of electrons as the minority carriers are generated in the p type semiconductor and the emission current is increased further by changing the electrons to the hot electrons by applying a high electric field to the thin depletion.