Does theory of quantum correction to conductivity agree with experimental data in 2D systems?

The quantum correction to the conductivity have been studied in two types of 2D heterostructures: with doped quantum well and doped barriers. The consistent analysis shows that in the structures where electrons occupy the states in quantum well only, all the temperature and magnetic field dependencies of the components of resistivity tensor are well described by the theories of quantum corrections. The contribution of electron-electron interaction to the conductivity have been determined reliably in the structures with different electron density. A possible reason of large scatter in experimental data concerning the contribution of electron-electron interaction, obtained in previous papers, and the role of the carriers, occupied the states of the doped layers, is discussed.Comment: 10 pages with 9 figure

Submonolayer Quantum Dots for High Speed Surface Emitting Lasers

We report on progress in growth and applications of submonolayer (SML) quantum dots (QDs) in high-speed vertical-cavity surface-emitting lasers (VCSELs). SML deposition enables controlled formation of high density QD arrays with good size and shape uniformity. Further increase in excitonic absorption and gain is possible with vertical stacking of SML QDs using ultrathin spacer layers. Vertically correlated, tilted or anticorrelated arrangements of the SML islands are realized and allow QD strain and wavefunction engineering. Respectively, both TE and TM polarizations of the luminescence can be achieved in the edge-emission using the same constituting materials. SML QDs provide ultrahigh modal gain, reduced temperature depletion and gain saturation effects when used in active media in laser diodes. Temperature robustness up to 100 °C for 0.98 μm range vertical-cavity surface-emitting lasers (VCSELs) is realized in the continuous wave regime. An open eye 20 Gb/s operation with bit error rates better than 10−12has been achieved in a temperature range 25–85 °Cwithout current adjustment. Relaxation oscillations up to ∼30 GHz have been realized indicating feasibility of 40 Gb/s signal transmission