InPBi thin films have been grown on InP by gas source molecular beam epitaxy. A maximum Bi composition of 2.4% is determined by Rutherford backscattering spectrometry. X-ray diffraction measurements show good structural quality for Bi composition up to 1.4% and a partially relaxed structure for higher Bi contents. The bandgap was measured by optical absorption, and the bandgap reduction caused by the Bi incorporation was estimated to be about 56 meV/Bi%. Strong and broad photoluminescence signals were observed at room temperature for samples with xBi < 2.4%. The PL peak position varies from 1.4 to 1.9 μm, far below the measured InPBi bandgap.

Resonances in ferroelectric phononic superlattice Appl. Phys. Lett. 101, 152902 (2012) Raman spectra investigation of InAlGaN quaternary alloys grown by metalorganic chemical vapor deposition J. Appl. Phys. 112, 063111 (2012) Temperature dependence of Mg-H local vibrational modes in heavily doped InN:Mg J. Appl. Phys. 112, 053528 (2012) Lamb wave band gaps in a homogenous plate with periodic tapered surface Phonon modes of PbTe films grown by molecular beam epitaxy have been studied by micro-Raman scattering. On the as-grown PbTe surface, strong TeO 2 phonon vibrational modes were detected, which obscured the observation of the longitudinal optical ͑LO͒ phonons of PbTe in early conventional Raman scattering experiments. Existence of a TeO 2 layer on the PbTe surface is confirmed by observation with x-ray photoemission spectroscopy. After removal of TeO 2 by chemical etching, the LO phonons for PbTe films were unambiguously observed. Misfit strain accommodated in the epitaxial films makes the lattice distorted from cubic structure, which lowers the crystal symmetry and leads to observation of what would normally be Raman inactive LO phonon modes for PbTe.

As a promising new class of near-infrared light emitters, GaAsBi laser diodes (LDs) are considered to have a high energy efficiency and an insensitive temperature dependence of the band gap. In this paper, we realize the longest ever reported lasing wavelength up to 1.142 μm at room temperature in GaAsBi 0.058 /GaAs quantum well LDs grown by molecular beam epitaxy. The output power is up to 127 mW at 300 K under pulsed mode. We also demonstrate continuous wave mode operation up to 273 K for the first time. The temperature coefficient of the GaAsBi/GaAs LD is 0.26 nm/K in the temperature range of 77−350 K, lower than that of both InGaAsP/InP and InGaAs/GaAs LDs. The characteristic temperature is extracted to be 139 K in the temperature range of 77−225 K and decreases to 79 K at 225−350 K.

InAs/InGaAs dot-in-well (DWELL) structures have been investigated with the systematically varied InGaAs thickness. Both the strained buffer layer (SBL) below the dot layer and the strain-reducing layer (SRL) above the dot layer were found to be responsible for the redshift in photoluminescence (PL) emission of the InAs/InGaAs DWELL structure. A linear followed by a saturation behavior of the emission redshift was observed as a function of the SBL and SRL thickness, respectively. The PL intensity is greatly enhanced by applying both of the SRL and SBL. Finite element analysis simulation and transmission electron microscopy (TEM) measurement were carried out to analyze the strain distribution in the InAs QD and the InGaAs SBL. The results clearly indicate the strain reduction in the QD induced by the SBL, which are likely the main cause for the emission redshift.