The authors demonstrate and characterize type-II GaSb quantum dot (QD) formation on GaAs by either Stranski-Krastanov (SK) or interfacial misfit (IMF) growth mode. mode selection is controlled the gallium to antimony (III/V) ratio where a high III/V produces IMF low establishes SK strain-relaxed QDs, QDs remain highly strained. Both ensembles strong room temperature photoluminescence (PL) with emitting at 1180nm 1375nm. Quantized energy levels along spectral blueshift are observed in 77K PL....

We discuss the results of a growth matrix designed to produce high quantum dot (QD) density, defect-free QD ensembles, which emit at 1.3 μm using metalorganic chemical vapor deposition (MOCVD). In our study, we balance nucleation rate and adatom surface migration achieve densities (1×1011 dots/cm2) avoid coalescence or defects that commonly characterize MOCVD-grown ensembles for longer wavelength emission. Room-temperature photoluminescence (PL) spectra from corresponding QDs depend on size...

We describe the growth mechanisms of highly mismatched (Δao∕ao=13%) defect-free AlSb on Si(001) substrates. Nucleation occurs during first few monolayers deposition by crystalline quantum dot formation. With continued growth, islands coalesce into a bulk material with no vertically propagating defects. Strain energy from AlSb∕Si interface is dissipated crystallographic undulations in zinc-blende lattice, as confirmed high-resolution transmission electron microscopy (TEM) images. Reciprocal...

The authors describe simultaneous interfacial misfit (IMF) array formation along with antiphase domain (APD) suppression in highly mismatched (Δa0/a0=13%) AlSb grown on a 5° miscut Si (001) substrate. Strain energy from the AlSb/Si heterojunction is accommodated by self-assembled two-dimensional of pure 90° dislocations confined to interface. 13% lattice mismatch establishes IMF period ∼3.46 nm. This spacing well matched step length Furthermore, substrate geometry suppresses APD due double...

We have introduced tensile layers embedded in a GaAs matrix to compensate compressive strain stacked 1.3μm InAs quantum dot (QD) active regions. The effects of the compensation are systematically investigated five-stack and ten-stack QD structures where we inserted InxGa1−xP (x=0.30 or 0.36) layers. High-resolution x-ray diffraction spectra quantify overall each sample indicate >35% reduction can be accomplished. Both atomic force transmission electron microscope images confirm that...

The authors report the optical characteristics of GaSb∕GaAs self-assembled quantum dots (QDs) embedded in an InGaAs well (QW). Variations In composition QW can significantly alter emission wavelength up to 1.3μm and efficiency. Lasing operation at room temperature is obtained from a 2-mm-long device containing five stacked GaSb QDs In0.13Ga0.87As QWs 1.026μm with threshold current density 860A∕cm2. probable lasing transition involves electrons holes confined QDs, respectively, resulting...

The authors report the formation and optical characteristics of type-II, strain-relieved, densely stacked GaSb∕GaAs quantum dots (QDs) using an interfacial misfit (IMF) growth mode. A moderate V/III ratio during GaSb QDs produces strain-relieved facilitated by IMF array without Sb segregation associated with defects threading dislocations. In contrast, a low establishes conventional Stranski-Krastanov QDs. strain-free nature allows packed, multistacked ensembles which retain very high...

We describe the growth and characterization of InAs quantum dots (QDs) on a patterned GaAs substrate using metalorganic chemical vapor deposition. The QDs nucleate (001) plane atop truncated pyramids formed by thin SiO2 mask. base diameter resulting varies from 30 to 40nm depending size With specific conditions, we are able form highly crystalline surface that emit at 1.6μm under room-temperature photopumped conditions. uniformity residual strain is quantified in high-resolution transmission...

We demonstrate an InAs∕GaAs quantum dot (QD) laser based on a strain-compensated, three-stack active region. Each layer of the stacked QD region contains thin GaP (Δao=−3.8%) tensile embedded in GaAs matrix to partially compensate compressive strain InAs (Δao=7%) layer. The optimized thickness is ∼4MLs and results 36% reduction our device structure. Atomic force microscope images, room-temperature photoluminescence, x-ray diffraction confirm that compensation improves both structural optical...

Monolithic vertical cavity surface emitting lasers (VCSELs) on Si are demonstrated. The GaSb multi-quantum well active region embedded in an Al(Ga)Sb half-wave spacer layer enables lasing under room-temperature optically-pumped conditions. 13% lattice mismatch is accommodated by a spontaneously formed 2-D array of 90° misfit dislocations at the AlSb/Si interface. This growth mode produces very low defect density (∼8×105/cm2) and relaxed materials (98%) without use buffer layer. Presented...

The authors report the formation of an interfacial misfit (IMF) array in growth relaxed GaAs bulk layers on a (001) GaSb surface. Under specific conditions, high quality IMF has period 5.6nm and can accommodate 7.78% tensile GaAs∕GaSb lattice mismatch. site is identified as 90° edge dislocation using Burger’s circuit theory confirmed by high-resolution cross-section transmission electron microscopy (TEM) images. resulting material both strain-free highly crystalline. Plan-view TEM images...

We present complete characterizations of multimode GaAs photodetectors for high-speed VCSEL-based optical links and compare SiGe receiver IC performances in a 62Gbps back-to-back link different photodiode designs.

The authors demonstrate a monolithic, electrically injected, vertically emitting GaSb∕AlGaSb light diode (LED) at 1.6μm comprised of hybrid GaAs∕GaSb-based structure. LED is quantum well/barrier active region embedded within high index contrast GaAs∕AlGaAs distributed Bragg reflectors (DBRs) using two interfacial misfit (IMF) arrays to relieve the strain induced from 8% lattice mismatch between material systems. first IMF formed under compressive conditions enable strain-free, defect-free...

A GaSb quantum-well (QW) laser diode grown monolithically on a 5° miscut Si (001) substrate is presented. The III-Sb epi-structure the via thin (50 nm) AlSb nucleation layer. 13% lattice mismatch between and accommodated by self-assembled, 2D array of interfacial misfit dislocations (IMF). geometry enables simultaneous IMF formation anti-phase domain suppression. 1 mm × 100 µm QW operates under pulsed conditions at 77 K with threshold current density 2 kA/cm2 maximum peak power ∼20 mW....

The authors report the device characteristics of GaInSb∕AlGaSb quantum well (QW) lasers monolithically grown on GaAs substrates. 7.8% lattice mismatch between substrates and GaSb buffer layers can be completely accommodated by using an interfacial misfit (IMF) array. Room-temperature lasing operation is obtained from a 1.25-mm-long containing six-layer Ga0.9In0.1Sb∕Al0.35Ga0.65Sb QWs at 1.816μm with threshold current density 1.265kA∕cm2. observed characteristic temperature coefficient are...

We report the device characteristics of stacked InAs∕GaAs quantum dots (QDs) with GaP strain-compensation (SC) layers grown by metal organic chemical vapor deposition. By inserting SC within structures, decrease in density QDs stacking can be suppressed due to reduction overall compressive strain QDs. demonstrate ground-state lasing at 1.265μm six layers. The threshold current is as low 108A∕cm2. also assess internal loss and maximum modal gain fabricated QD lasers using a segmented contact...

Room-temperature optically-pumped In0.2Ga0.8Sb quantum well lasers on Si are reported. The defect-free monolithic epistructure growth a Si(100) substrate is initiated by an AlSb dot nucleation layer followed AlSb/GaSb superlattice. 13% mismatch between the and lattice accommodated misfit dislocations associated crystallographic undulations in buffer. buffer characterised atomic force microscopy transmission electron microscopy. lasing spectrum as function of pump power polarisation analysis.

We report a highly effective growth technique to both dissolve large islands and prevent further defect propagation in closely spaced (15nm) stacked quantum dot (QD) active regions while maintaining an emission wavelength >1.3μm. Island dissolution is accomplished via In flush, which AsH3 pause inserted into the sequence just after each QD layer capped. The low V∕III ratio enables flushing of surface atoms from sites fully capped QDs remain intact. This eliminates need for situ...

We report and characterize the growth of defect-free AlSb bulk material on Si (001) substrates using a monolithic self-assembled quantum dot (QD) nucleation layer. During first few monolayers Si, highly crystalline QDs form. With continued deposition, islands coalesce into planar with no detectable defects. The QD layer facilitates completely relaxed within ∼100 ML deposition according to x-ray diffraction. attribute success both large AlSb∕Si lattice mismatch (Δa0∕a0=13.5%) in combination...