The band gap of AlxGa1−xN is measured for the composition range 0⩽x<0.45; the resulting bowing parameter, b=+0.69 eV, is compared to 20 previous works. A correlation is found between the measured band gaps and the methods used for epitaxial growth of the AlxGa1−xN: directly nucleated or buffered growths of AlxGa1−xN initiated on sapphire at temperatures T>800 °C usually lead to stronger apparent bowing (b>+1.3 eV); while growths initiated using low-temperature buffers on sapphire, followed by high-temperature growth, lead to weaker bowing (b<+1.3 eV). Extant data suggest that the intrinsic band-gap bowing parameter for AlGaN alloys is b=+0.62(±0.45) eV.

Direct observation of anti-phase boundaries in heteroepitaxy of GaSb thin films grown on Si(001) by transmission electron microscopy J. Appl. Phys. 112, 074306 (2012) Carrier recombination lifetime in InAs thin films bonded on low-k flexible substrates AIP Advances 2, 042105 (2012) Tunability of intersubband transition wavelength in the atmospheric window in AlGaN/GaN multi-quantum wells grown on different AlGaN templates by metalorganic chemical vapor deposition J. Appl. Phys. 112, 063526 (2012) Anomalous temperature dependence of photoluminescence in self-assembled InGaN quantum dots Appl. Phys. Lett. 101, 131101 (2012) Optical properties of InGaPN epilayer with low nitrogen content grown by molecular beam epitaxy

Ordering on the fl 1 1} planes of the group-V sublattice (CuPt type) is demonstrated in molecularbeam-epitaxy grown InAs~-, Sb (x =0.4) alloys and strained-layer superlatiices (SLS's) using transmission electron diffraction. Accompanying ordering, a significant reduction of the band gap of the alloy was observed through infrared photoluminescence and photoconductive response measurements. An ordered SLS displayed a photoresponse at longer wavelength than the ordered alloy, due to a type-II band offset of the ordered constituents of the SLS. The band-gap reduction caused by ordering in these samples indicates that InAsl-Sb, alloys can effectively span the 8-12-pm atmospheric window for long-wavelength, infrared-detector applications. There is considerable interest in InAs~, Sb"alloys and heterostructures for (III-V)-based, long-wavelength detectors and sources. With a type-II (or staggered) band off'set, InAsi, Sb, strained-layer superlattices (SLS's) have displayed photoresponses at wavelengths )10 pm, '2 and prototype long-wavelength infrared (LWIR) photodiodes have been constructed. 3 However, the minimum band gap reported for InAsi, Sb, alloys grown by molecular-beam epitaxy (MBE) is 145 meV (8.6 pm), observed in InAsu37SbQ63 at low temperature. The band gapa of disordered InAs~, Sb, alloy samples grown by zone recrystallization were in close agreement with those observed in recent M BE samples. Based on previous work, intrinsic InAs~-, Sb, alloys appeared unable to span the 8-12 pm atmospheric window for LWIR detector applications.Recently, compositional ordering on the f1 1 1} planes has been observed in a number of III-V ternary systems, ' including InAsi, Sb, . ' Pseudopotential calculations for completely ordered ternaries with 50%-50% compositions indicate that a significant reduction of the direct band gap will result, and a semimetal may occur for completely ordered InAs05Sbu5. ' Previously, there has been no report of the optical properties of ordered InAs~, Sb, materials. In this paper we determine the band gap of an ordered InAs~, Sb, (x =0.4) alloy and SLS using infrared photoluminescence and photoconductive response measurements. Significant band-gap reduction is observed for these samples, and this initial study demonstrates that ordered InAs~-, Sb, alloys need to be reexamined for device applications requiring high speed or long-wavelength photoresponse.InAsl, Sb"samples were grown using MBE. For the I nAs l -, Sb"material, the growth temperature was 425 C, and the growth rate was I pm/h. The growth temperature used in this study was lower than that reported in other MBE studies of InAsI -"Sb, alloys, thus promoting ordering. Elemental sources were used to produce the In and Sb4 beams. As2 was generated by thermal cracking at 900 C. A total group-V:group-III equivalent pressure ratio of = 3.0 was used for InAsl Sb"growth.Sample quality must be maintained in order to observe photoluminescence and sharp absorption edges. To re-duce dislocations resulting from lattice mismatch of the InAsi, Sb,...

Gas-phase parasitic reactions among TMG, TMA, and NH3, are investigated by monitoring of the growth ratehncorporation efficiency of GaN and AlN using an in-situ optical reflectometer. It is suggested that gas phase adduct (TMA: NH3) reactions not only reduce the incorporation efficiency of TMA but also affect the incorporation behavior of TMGa. The observed phenomena can be explained by either a synergistic gas-phase scavenging effect or a surface site-blocking effect. Relatively low reactor pressures (30-50 Torr) are employed to grow an AlGaN/GaN QW p-n diode structure. The UV emission at 354 nm (FWHM -6 nm) represents the first report of LED operation from an indium-free GaN QW diode.

Heterostructures with biaxially compressed, As-rich InAsSb are being investigated as active regions for midwave infrared emitters. InAs1−xSbx/In1−xGaxAs (x≊0.1) strained-layer sublattices (SLSs), nominally lattice matched to InAs, were grown using metalorganic chemical vapor deposition. An SLS light-emitting diode was demonstrated which emitted at 3.6 μm with 0.06% efficiency at 77 K. Optically pumped laser emission at 3.9 μm was observed in a SLS/InPSb heterostructure. The laser had a maximum operating temperature of approximately 100 K.