Intervalence-band THz laser in selectively-doped semiconductor structure

Terahertz Gain on Intersubband Transitions in Multilayer Delta-Doped p-GaAs Structures

“…In contrast to p-Ge/Ge structures [7][8][9][10], the optimal average carrier concentration for the delta doped p-GaAs/GaAs structure is comparable to that for uniformly doped p-GaAs [4] and equal to ~ 2x10 14 -4x10 14 cm -3 . The optimal range of the structure period is 250 -500 nm for the chosen fields.…”

“…GaAs (fields, average concentration, temperature) except the doping profile, so that the observed improvement is a purely effect of the selective doping. As will be shown below, an additional improvement of the gain by increase in the carrier concentration, as was observed for p-Ge/Ge structures [7][8][9][10], is not achievable for GaAs. Comparison of Figs.…”

Amplification of terahertz radiation in delta-doped germanium thin films

“…Our practical goal is development of a terahertz laser based on thin germanium films with small signal gain coefficient sufficient to operate at liquid nitrogen temperatures. An additional motivating factor for pursuing our approach, when THz quantum cascade lasers have already achieved this temperature milestone 4,5 , is the unique very wide gain spectrum (2)(3)(4) for the transitions between subbands of the valence band. This feature is potentially important for building a terahertz laser with wide tunability, which none of the other known terahertz semiconductor lasers possesses.…”

Inter-Valence-Band Hot Hole Laser in Two-Dimensional Delta-Doped Homoepitaxial Semiconductor Structures

“…Figure 4 explains clearly the importance of impurity scattering on the gain. 26 While the gain g is proportional to the number of holes N , the gain g = Nσ Fig. 4.…”

“…Gain cross section as a function of acceptor cross-section as determined from Monte-Carlo simulated hot-hole distribution functions. 26 Gain is the product of cross section and hole concentration. The maximum gain occurs near 10 14 cm −3 .…”