Instability of current and N-shaped current-voltage characteristic in a silicon p-i-n diode subjected to a magnetic field

Experimental results of studying the p-i-n structures based on n-Si with the resistivity ρ = 120 Ω cm are reported. The dynamic S-shaped current-voltage characteristics were studied at various values of the applied magnetic field. Initiation of the current and voltage large-amplitude oscillations was observed at a magnetic field of 2 kOe. A further increase in the magnetic field leads to an increase in the amplitude of oscillations and to the appearance of a high-frequency oscillation mode with the frequency of ∼ 3 MHz; this mode modulates the low-frequency mode. A magnetic field in excess of 5 kOe reduces the amplitude of both modes of current oscillations and completely suppresses oscillations in the circuit so that the S-shaped form of the current-volt-age characteristic disappears. In accordance with the theory, experimental current-voltage characteristics were observed for the first time to feature portions with negative differential N-type conductivity in the presence of a high magnetic field and with the chosen sample configuration and relevant values of electric field.