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Articles you may be interested inTime-resolved photoluminescence of lithographically defined quantum dots fabricated by electron beam lithography and wet chemical etching Low voltage electron-beam lithography based InGaAs/GaAs quantum dot arrays with 1 meV luminescence linewidths J.High quantum efficiency InGaAs/GaAs quantum wires defined by selective wet etching

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Using electron beam lithography and wet chemical etching we have developed single InGaAs/GaAs quantum dots with diameters between 200 nm and 40 nm. The lithographic definition permits the dot shape as well as the dot size to be controlled. In addition to circular dots, which allow the transition between twoand zero-dimensional systems to be studied, we have fabricated rectangular dots which can be used to study the changeover from one-to zero-dimensional structures. Photoluminescence spectra of the dots show a lateral quantization-induced increase of the bandgap energy as well as emission of higher dot states. The experimental results for the lateral confinement energies can be described well by numerical calculations. The average number of electron-hole pairs in the dot can be derived from different features of the spectra. With decreasing dot diameter we observe a continuous reduction of the luminescence linewidths in our structures. This variation is consistent with a decrease of elastic scattering processes by well widths and compositional fluctuations for reduced dot size.

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