Optical properties of modulation-doped quantum wires fabricated by electron cyclotron resonance reactive ion etching

Modulation-doped GaAs/AlGaAs quantum wires have been fabricated using electron-beam lithography followed by electron-cyclotron resonance reactive ion etching to selectively deplete the electron gas. This technique has the advantages of low damage to the quantum well, strongly anisotropic etching, and reproducible control over the etch depth. The quantum wires exhibit high photoluminescence efficiencies when etched as close as 200 Å to the electron gas. The fundamental gaps show the large optical red shifts associated with strongly spatially indirect transitions. The spacings between one-dimensional subbands determined from inelastic light scattering measurements are larger than 2 meV.