High Quantum Efficiency of Intersubband Transision on Combined Parity Levels in Triple-Barrier Structures

Exact analytical steady-state solution of the time-dependence Schrodinger equations at resonance in hf electric field of finite amplitude is found as well as expression for hf active conductivity. It is shown that if the energy levels in each quantum well which form the common resonance level of the whole structure have the different parity, the common resonance level width and integral hf structure conductance can rise many times and quantum efficiency of radiative transitions between dimensionally quantized levels can be up to 80 %. Respectively, the electron life time in structure fall many times, so the conditions for electron to leave the structure without electron-phonon collision can be simply realized, and one has the real way for realization of ballistic electron transport quantum-cascade laser