Fabrication of dry etched CdZnSe/ZnSe quantum wires by thermally assisted electron cyclotron resonance etching

Abstract

A low damage dry etch technology suitable for in situ processing was developed for the fabrication of ZnSe-based nanostructures. Thermally assisted electron cyclotron resonance etching combines plasma etching at low ion energies with process temperatures between 80°C and 210°C. Due to a variation of the process parameters, i.e., plasma power and sample temperature, a transition from partially physical to prevailing chemical etch properties is obtained. Therefore an accurate control of etch profile, surface morphology, and etch rate is possible. Optically active CdZnSe/ZnSe quantum wires with lateral sizes down to 20 nm were realized, indicating a significantly reduced influence of optically inactive layers compared to conventionally dry etched nanostructures. In narrow wires, a systematic blue shift of the photoluminescence signal with decreasing wire width clearly demonstrates lateral carrier confinement effects.