Interband and intersubband absorption in HgCdTe multiple quantum wells

We present calculated and experimental interband and photoinduced intersubband absorption spectra for undoped HgCdTe multiple quantum wells. The results show that there is an enhancement of the interband absorption at energies close to the barrier energy for electrons. The calculated interband absorption, based on a full $8\times 8\hspace{0.5em}\mathbf{k}\cdot \mathbf{p}$ Kane model to obtain the electronic structure, predicts that this absorption enhancement is caused by an increase in the electron-hole joint density of states due to band mixing for confined and continuous electron states. The photoinduced electron intersubband absorption presents an asymmetric line shape due to the nonparabolic bands. The calculated spectra reproduce well the experimental results.