Free-carrier absorption in Be- and C-doped GaAs epilayers and far infrareddetector applications

Far infrared (FIR) absorption, reflection, and transmission in heavily dope d p-GaAs multilayer structures have been measured for wavelengths 20-200 mu m and compared with the calculated results. Both Be (in the range 3x10(18)- 2.6x10(19) cm(-3)) and C (1.8x10(18)-4.7x10(19) cm(-3))-doped structures we re studied. It is found that the observed absorption, reflection, and trans mission are explained correctly by the model with a dominant role of free-c arrier absorption in highly doped regions. High reflection from heavily dop ed thick layers is attractive for the resonant cavity enhanced FIR detector s. (C) 2001 American Institute of Physics.