TERAHERTZ RESPONSE OF ZERO-DIMENSIONAL STATES IN RESONANT-TUNNELING DIODES

The photoresponse of zero-dimensional states in double barrier resonan t tunneling diodes has been observed using high intensity THz radiatio n (photon frequencies ranging from 4 to 10 THz) from a free-electron l aser. The double barrier resonant tunneling diodes have silicon donors in the quantum well which act as individual localized tunneling chann els. The high frequency response of these diodes shows additional feat ures due to the presence of these extra channels. The temperature depe ndence allows us to identify the contribution of the zero-dimensional states. The absence of wavelength dependence in the observed photoresp onse indicates that photoassisted tunneling does not occur under these measurement conditions. (C) 1995 American Institute of Physics.