PHOTOCURRENT ABSORPTION SPECTROSCOPIC STUDY OF Si0.6Ge0.4/Si QUANTUM WELLS

Abstract

Absorption spectra of Si 0.6 Ge 0.4/ Si quantum wells are characterized by photocurrent measurements. The absorption coefficients of two different transitions, namely the transition between the Si band states and the discrete energy level in quantum wells, and the interlevel transition in quantum wells are deduced. They are directly proportional to (ℏω-ΔE)3/2 and δ(ℏω-Eeh), respectively. The valence band offsets of Si 0.6 Ge 0.4/ Si interface are 297 meV. The ground state energy levels in valence band and conduction band Si 0.6 Ge 0.4/ Si quantum wells are 37 meV and 23 meV, respectively.