Quantum Wells Of Different Widths Research Articles

Measurement of the hole dispersion in a quantum well by hot-electron-acceptor luminescence.

We report quantitative measurements of the hole dispersion curves of a quantum well using hot-electron-acceptor luminescence in combination with band-edge luminescence. The directionally averaged heavy-hole and light-hole energies are determined for in-plane wave vectors between 3% and 7% of the Brillouin zone. Experimentally significant differences between quantum wells of different widths are observed.

Influence of barrier height on carrier dynamics in strained InxGa1-xAs/GaAs quantum wells.

Strained ${\mathrm{In}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$As/GaAs heterostructures with different In content x, each containing quantum wells with various well widths ${\mathit{L}}_{\mathit{z}}$ (between 2 and 30 nm) are investigated with use of time-integrated and time-resolved spectroscopy. With increasing temperature, a characteristic drop of both the photoluminescence (PL) intensity and PL lifetime is observed, revealing a strong dependence on In content and well width. The temperature dependencies can be explained by thermal emission of the carriers out of rather shallow quantum wells. The transfer of the carriers between quantum wells of different widths across the GaAs barrier is demonstrated and described by a system of rate equations.

Optical studies of electron and hole Fermi seas in a single GaAs/AlxGa1-xAs quantum well.

The optical properties of a sample containing several GaAs quantum wells of different widths separated by relatively thick but leaky ${\mathrm{Al}}_{0.3}$${\mathrm{Ga}}_{0.7}$As barriers are investigated at temperatures up to 150 K. Electrical bias, applied using a Schottky gate, tilts the energy bands and results in quasiresonant transfer of electrons or holes, photoexcited in thicker GaAs layers into the quantum wells. This permits investigations under conditions varying from no significant carrier population up to electron or heavy-hole sheet densities of about 2\ifmmode\times\else\texttimes\fi{}${10}^{11}$ ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}2}$ in the same quantum well and provides detailed information on the formation of ``Mahan excitons,'' oscillator strengths, and band-gap renormalization.

Photoluminescence and photoluminescence excitation study of electron-hole tunneling in In 0.53Ga 0.47As/InP coupled-single quantum wells

Electron and hole tunneling is observed by photoluminescence and photoluminescence excitation spectroscopies in In 0.53Ga 0.47As/InP samples incorporating two quantum wells of different widths separated by 20–100 Å wide barriers. For 20 Å wide barriers the two associated emission lines due to confined excition recombination thermalize with activation energies demonstrating directly combined electron and hole tunneling through the barriers. From such data and measured luminescence decay times lower bounds for the tunneling rates are inferred.