Raman investigation of CdxZn1−xSe/ZnSe quantum wires: length dependence of the strain relaxation

Abstract We present a Raman spectroscopic investigation of etched CdZnSe quantum wires and short wires (quantum dots). The investigated samples consist of 5 and 3 nm thick quantum wells with a cadmium content of 20% and 35%, respectively. From these wells wires and short wires with different lengths and widths were etched. The Raman signal in the ZnSe LO phonon region can be separated into three modes: one at 256 cm −1 is due to the ZnSe barrier material, whereas the signal of the CdZnSe wire material is split into two modes. The lower energy peak of the wire material occupies the wavenumber position of the unstrained wire material and shows no shift with decreasing wire length. Consequently, we assign it to the totally relaxed edges of the wire. The higher energy peak is assigned to the wire center and shows a small redshift towards the other peak, which is due to a further strain relaxation of the wire center with decreasing wire size.