Direct magneto-optical observation of a quantum confined one-dimensional electron gas

The energy spectra of isolated one-dimensional (1D) electron channels have been studied by photoluminescence in zero and finite magnetic fields B. Arrays of periodic quantum wires (period =290--400 nm, width =150--170 nm) were etched from modulation-doped Alₓ{Ga}_{1{{-}}x}$As/GaAs heterojunctions, with special low-concentration Be {δ} doping in the buffer layer to increase the photoluminescence intensity. We were able to attain the 1D quantum limit, i.e., occupation of only the lowest 1D subband at B=0, and to measure, at small B, a characteristic quadratic B dispersion of the 1D subband edge.