Y.Q. Wei

Large ground-to-first-excited-state transition energy separation for InAs quantum dots emitting at 1.3 μm

By capping InAs quantum dots (QDs) with a thin intermediate layer of InAlAs instead of GaAs, the radiative transition wavelengths are redshifted. Surface morphology studies confirm that the redshift is due to a better preserved QD height as compared with capping by GaAs only. In contrast, the energy levels are blueshifted when using AlGaAs instead of GaAs as the barrier material. In both cases, the energy separation between the ground and the first-excited state increases significantly. Combining these approaches, we demonstrate InAs QDs with a record transition energy separation of 108 meV and ground-state emission at 1.3 μm.

1.3 to 1.5 μm light emission from InGaAs/GaAs quantum wells

We propose using dipole δ-doping across highly strained InGaAs/GaAs quantum wells (QWs) to achieve light emission at wavelengths in the range of 1.3–1.55 μm. For In0.3Ga0.7As/GaAs single QWs, we demonstrate that the photoluminescence (PL) wavelength increases with the doping concentration. With a transition energy reduction as large as 370 meV, PL emission at 1.548 μm at room temperature is realized. Broad area lasers with dipole δ-doping reveal longer lasing wavelengths than those of undoped lasers, although the wavelength redshift is much less than in the PL case.

High-quality GaNAs∕GaAs quantum wells with light emission up to 1.44μm grown by molecular-beam epitaxy

High-quality GaNAs/GaAs quantum wells with high substitutional N concentrations, grown by molecular-beam epitaxy, are demonstrated using a reduced growth rate in a range of 0.125-1 mu m/h. No phase separation is observed and the GaNAs well thickness is limited by the critical thickness. Strong room-temperature photoluminescence with a record long wavelength of 1.44 mu m is obtained from an 18-nm-thick GaN0.06As0.94/GaAs quantum well

Strong 1.3–1.6μm light emission from metamorphic InGaAs quantum wells on GaAs

We demonstrate strong 1.3-1.6 mu m photoluminescence (PL) from InGaAs quantum wells (QWs) grown on alloy graded InGaAs buffer layers on GaAs by molecular beam epitaxy. The epistructures show quite ...

10 Gbps Modulation of 1.3 μm GaInNAs Lasers up to 110°C

We demonstrate uncooled 10 Gbps operation of 1.3 μm ridge waveguide GaInNAs lasers with a double quantum well active region up to 110°C. The low temperature sensitivity enables the use of a constant modulation voltage

1.3-1.55 /spl mu/m light emission from InGaAs/GaAs quantum wells on GaAs using dipole /spl delta/-doping

We propose a new method for 1.3-1.55 /spl mu/m lasers on GaAs using dipole /spl delta/-doping and demonstrate extension of photoluminescence wavelength from 1.07 to 1.55 /spl mu/m in InGaAs/GaAs quantum wells at room temperature.

Wavelength extension of highly-strained InGaAs/GaAs quantum well laser diodes by dipole /spl delta/-doping

We demonstrate the wavelength extension of InGaAs/GaAs quantum well (QW) laser diodes (LD) by dipole /spl delta/-doping (DDD). This is achieved by introducing n- and p-type /spl delta/-doping close to each side of the QW, respectively. As a result, the internal electric field causes band bending which reduces the interband transition energy. Using this method, the lasing wavelength of an In/sub 0.36/Ga/sub 0.64/As/GaAs QW LD is shifted from 1.175 /spl mu/m to 1.206 /spl mu/m. Although electroluminescence shows that the lasing comes from electron and hole recombination in the excited states, we believe that this may provide a new method for long-wavelength InGaAs/GaAs QW laser fabrication.

Photoluminescence comparation of InAs quantum dots with different capping

We have studied the effect of different cap layers on optical property of InAs quantum dots (QDs) on GaAs (100) substrate. Temperature dependent photoluminescence (PL) indicates that the PL integrated Zn intensity from the ground state of InAs QDs capped with an intermediate InAlAs/InGaAs combined layer drops very little as compared to QDs capped with a thin InGaAs or GaAs layer from 15 K up to room temperature. PL integrated intensity ratio of the first excited to ground states for InAs QDs capped with an intermediate InAlAs/InGaAs layer is unexpectedly decreased with increasing temperature, which we tentatively attribute to phonon bottleneck effect.

Aluminium incorporation for growth optimization of long-wavelength InAs/GaAs quantum dots by molecular beam epitaxy

Summary form only given. We investigate the use of Al in both the lower and the upper embedding layers. We demonstrate that increasing the Al content in the lower InAlGaAs embedding layer increases the QDs density dramatically while introducing a thin InAlAs cap layer can increase the QDs density and also tune the InAs QD ground state emission wavelength to 1.3 /spl mu/m and increase the energy separation between the ground and the first excited state transitions. AFM and PL spectra were used to characterize the QDs.