Inhomogeneous strain in individual quantum dots probed by transport measurements

Resonant tunneling measurements are used to probe the inhomogeneous strain in individual SiGe quantum dots. Current-voltage characteristics of strained Si/SiGe resonant tunneling diodes of diameter D less than or equal to 0.25 mu m exhibit additional fine quasi-periodic structure in the resonant peaks. The fine structure is consistent with lateral quantization in the SiGe quantum well due to in-plane confining potentials arising from inhomogeneous strain, which we calculate by finite element techniques for various D. Quenching of the fine structure by a magnetic field is consistent with the effective length scale of the strain-induced potential. (C) 1998 American Institute of Physics. [S0003-6951(98)01514-9].