Amplification of space charge waves in n-InN films of THz range

Generation of sequences of strong electric monopulses in nitride films

“…The relaxation frequency w in n-InN is smaller than in n-GaN; this fact limits the frequency range of the amplification of SCW in the n-InN films [15].…”

“…w00 = 0.039 eV is the average electron energy at 300 K; E00  E0z is the bias constant electric field. It is assumed that p, w, m * are the functions of the average electron energy w. An influence of the thermoconductivity on the electron gas dynamics is not essential up to the frequencies f  2 -3 THz [15]. The electron kinetic energy for the investigated processes is one order lower than the average electron energy, so it is T  (2/3)w.…”

“…The dependencies of the relaxation frequencies were computed from Eqs. (1) in the stationary case /t = 0 [1,[15][16][17][18][19]; the dependencies in Fig. 2, a), b), were used.. Their computed values are p 2•10 13 s -1 for both nitrides; w  10 12 s -1 for InN, w  10 13 s -1 for GaN [15].…”

“…Recently it was demonstrated that n-InN possesses the increased values of the negative differential conductivity (NDC), probably the highest ones between the semiconductor materials [13,14]. The space charge waves (SCW) in n-GaN and n-InN films can be amplified due to NDC, when the magnitudes of bias electric fields are higher than the critical, or threshold, ones [15].…”

“…The linear amplification of SCW in n-GaN and n-InN films was investigated in the frequency range f < 800 GHz, where the non-local dependence of the electron velocity on the average electron energy was taken into account [15][16][17]. The typical thicknesses of the films were 2l = 0.2 -1 m, their lengths were 10 -50 m, see Fig.…”