High-resolution definition of buried InGaAs/InP wires by selective thermal intermixing

Abstract

Buried InGaAs/InP wire structures with widths down to 30 nm by using a new and simple fabrication technique have been developed. The key point is the local removal of the InP top barrier layer of an InGaAs/InP quantum well using high-resolution electron-beam lithography and selective wet chemical etching. The patterned sample is then subjected to a rapid thermal annealing step. The InGaAs surface quantum wells, formed in the etched parts of the samples, display an enhanced interdiffusion compared to conventional quantum wells covered with an InP cap layer. This leads to a local increase of the band gap, which confines the carriers to the InP covered regions. The wires show sharp photoluminescence emission bands even for the smallest wire widths and a significant increase of the emission intensity due to carrier capture from the vertical and lateral barriers.