We propose and realize a substrate-free metal-cavity surface-emitting microlaser with both top and sidewall metal and a bottom distributed Bragg reflector as the cavity structure. The transfer-matrix method is used to design the laser structure based on the round-trip resonance condition inside the cavity. The laser is 2.0 m in diameter and 2.5 m in height, and operates at room temperature with continuous-wave mode. Flip-bonding the device to a silicon substrate with a conductive metal provides efficient heat removal. A high characteristic temperature about 425 K is observed from 10 to 27 °C.
Eliminating the fine structure splitting of excitons in self-assembled InAs/GaAs quantum dots via combined stresses Appl. Phys. Lett. 101, 063114 (2012); 10.1063/1.4745188 Electrical control of fine-structure splitting in self-assembled quantum dots for entangled photon pair creation Appl. Phys. Lett. 97, 221108 (2010); 10.1063/1.3522655 Exsitu control of finestructure splitting and excitonic binding energies in single InAs/GaAs quantum dots AIP Conf.
An optically pumped semiconductor disk laser using submonolayer quantum dots (SML QDs) as gain medium is demonstrated. High-power operation is achieved with stacked InAs∕GaAs SML QDs grown by metal-organic vapor-phase epitaxy. Each SML-QD layer is formed from tenfold alternate depositions of nominally 0.5 ML InAs and 2.3 ML GaAs. Resonant periodic gain from a 13-fold nonuniform stack design of SML QDs allows to produce 1.4W cw at 1034nm. The disk laser demonstrates the promising potential of SML-QD structures combining properties of QD and quantum-well gain media for high-power applications.
Electrical operation of single photon emitting devices employing site-controlled quantum dot (QD) growth is demonstrated. An oxide aperture acting as a buried stressor structure is forcing site-controlled QD growth, leading to both QD self-alignment with respect to the current path in vertical injection pin-diodes and narrow, jitter-free emission lines. Emissions from a neutral exciton, a neutral bi-exciton, and a charged exciton are unambiguously identified. Polarization-dependent measurements yield an exciton fine-structure splitting of (84 ± 2) μeV at photon energies of 1.28–1.29 eV. Single-photon emission is proven by Hanbury Brown and Twiss experiments yielding an anti-bunching value of g(2)(0) = 0.05 under direct current injection.
Using cross-sectional scanning tunneling microscopy and photoluminescence spectroscopy, the atomic structure and optical properties of submonolayer depositions of InAs in GaAs are studied. The submonolayer depositions are formed by a cycled deposition of 0.5 monolayers InAs with GaAs spacer layers of different thicknesses between 1.5 and 32 monolayers. The microscopy images exhibit InAs-rich agglomerations with widths around 5 nm and heights of up to 8 monolayers. A lateral agglomeration density in the 1012cm -2 range is found. During the capping of the InAs depositions a vertical segregation occurs, for which a segregation coefficient of 0.73 was determined. In the case of thin GaAs spacer layers, the observed segregation forms vertically connected agglomerations. The photoluminescence spectra exhibit peaks with linewidths below 10 meV and show a considerable dependence of the peak energy on the spacer thickness, even up to 32 monolayers GaAs, indicating a long range e lectronic coupling
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