In0.3Ga0.7N/GaN multiple quantum wells have been grown on the epitaxial lateral overgrowth GaN successfully. The samples have been characterized by transmission electron microscopy and x-ray diffraction, which show the high quality of the samples. Photoluminescence measurements have been carried out at room temperature, with back scattering geometry. At a low excitation power, only exciton-related emission has been observed at 3.1935 eV. With increasing excitation power, a peak appears at the low-energy side of the exciton-related emission, and becomes dominant at high excitation power. This peak has been assigned to plasma emission, because the intensity of this peak increases with excitation power as I-ex(1.9).

“removed due to double publication”. The original paper: Journal: Semiconductor Science and Technology Create an alertIssue Volume 15, Number 6 Citation: L S Tan et al 2000 Semicond. Sci. Technol. 15 585 doi: 10.1088/0268-1242/15/6/317 can be accesses at IOP: http://iopscience.iop.org/0268-1242/15/6/317

The effects of plasma etching on 1/f noise and photoluminescence (PL) characteristics of n-GaN have been investigated. A reduction of 1/f noise was observed after plasma exposure, a result of enhanced passivation of the reactive surface. This is attributed to the removal of carbon and the creation of a Ga-rich surface by the etching process. Nevertheless, the formation of nonradiative recombination centers impaired the PL intensity. Reconstruction of a stoichiometric surface was achieved by annealing. This induced the incorporation of carbon into GaN, deteriorating the PL performance further, but it could be restored by a chemical treatment of 10:1 HF:H2O.

We report the growth and characterization of GaInAsP films on GaAs substrates by solid source molecular beam epitaxy (SSMBE) using a valve phosphorous cracker cell at varied white phosphorous beam equivalent pressure (BEP). It is found that the GaInAsP/GaAs can be easily grown with the solid sources, and the incorporated phosphorous composition as a function of the beam equivalent pressure ratio, R=fP/(fP+fAs), can be well described by a parabolic relationship. With the increase of the incorporated phosphorous composition, the GaP-, InP-, InAs- and GaAs-like phonon modes shift towards opposite directions and their emission intensities also change. The first three modes shift to larger wave numbers while the last one shifts to smaller wave number. The lattice mismatch, Δa/a, of the materials grown with varied phosphorous BEP follows a linear relationship. Photoluminescence (PL) measurements reveal that as the phosphorous BEP ratio increases, the peak position or energy band gap of the material shifts towards higher energy; the full-width at half-maximum (FWHM) becomes narrower, and the luminescence intensity becomes higher. In addition, the materials also show smooth surfaces that do not change significantly with phosphorous beam equivalent pressure.

The effect of growth interruption on the top interface of the InGaAs layer in InP/In0.53Ga0.47As/InP heterostructures grown by molecular beam epitaxy was studied by Hall measurements, photoluminescence (PL) spectroscopy and high-resolution X-ray diffraction (HR-XRD). PL results from multiple quantum well structures (three: stacked InGaAs quantum wells of 10, 20 and 40 Angstrom width lattice matched to 300 Angstrom InP barriers) indicated an optimum interruption time of similar to 70 s for obtaining the minimum PL line width. Lattice matched high-electron mobility transistor structures were grown using different growth interruption times similar to MQW structures. A maximum electron mobility of 3500 cm(2)/Vs and 15 900 cm(2)/V s at 300 K and 77 K, respectively, was measured. This time approximately corresponds to the minimum PL line width obtained for the quantum well structure. The variation of the electron mobility with the growth interruption time was attributed to the formation of a thin InAsP or InGaAsP layer on the surface of the InGaAs at the InGaAs/InP heterointerface similar to MOVPE-grown samples. PL and HR-XRD results indicate that a similar phenomenon may be operative in MBE-grown layers also, and an optimum interruption time may provide abrupt interfaces with better electrical and optical properties. (C) 2000 Elsevier Science B.V. All rights reserved.

We report the effects of arsenic beam equivalent pressure on lattice mismatch, electrical properties, surface roughness and morphology of InGaAsP grown by solid source molecular beam epitaxy using valve arsenic and phosphorous cracker cells with continuous white phosphorous production. Arsenic is found to have a higher sticking coefficient than phosphorous in almost all arsenic pressure employed in the growth. The incorporation of arsenic is found to fit a polynomial expression, Y=1.56R−0.59R2, with the beam equivalent pressure ratio R=fAs/(fAs+fP). The incorporated arsenic elements significantly affect lattice mismatch and electrical properties. They also dominate surface construction of the quaternary material.

In this paper, the design and analysis of a double barrier quantum well infrared photodetector is described Analyses of the effects of the material composition, well width and barrier width on the response wavelength and oscillator strength are carried out using the transfer matrix method. The results are applied to the design of a GaAs/AlGaAs/InGaAs/AlGaAs/GaAs photodetector operating at a wavelength of 3.72 mu m.

In this paper we illustrate the power and utility of quantitative mobility spectrum analysis (QMSA) of magnetic field dependent Hall data in order to evaluate the transport parameters of multilayer III–V materials and device structures such as high electron mobility transistors (HEMTs) and heterojunction bipolar transistors (HBTs). As a first example, we present the QMSA of a n + GaAs/GaAs/n + AlGaAs/p + GaAs/n GaAs/n + GaAs HBT structure, in which QMSA resolves two carrier species: holes with mobility of 700 cm 2 V −1 s −1 and density 1.6 × 10 18 cm −3 , and electrons with mobility of 1530 cm 2 V −1 s −1 and density 3.0 × 10 18 cm −3 . A direct comparison with the results of C-V electrochemical profiling indicates that all n + -type layers (sub-collector, emitter and cap) are characterised by an electron mobility which appears in the mobility spectrum as a single peak with an average density corresponding to the sum of all three n + layers. The peak in the hole spectrum may be clearly identified with the single p-type base layer. The second example is an n −1 GaAs/n + AlGaAs/AlGaAs/GaAs HEMT structure in which the 2D electron gas population with a mobility of 7750 cm 2 V −1 s −1 and sheet density of 2.6 × 10 11 cm −2 is readily identified and separated from the mobility spectrum peak corresponding to the two highly-doped n-type capping layers. Due to the similar carrier mobility in both capping layers, their contribution to the spectrum appears as a single electron peak at 1100 cm 2 V −1 s −1 with a density of 2.1 × 10 16 cm −3 .

The I-V/C-V characteristics of Schottky diodes fabricated on InGaAlAs/InP heterostructures are reported with Al mole fraction varying in the quaternary alloy. InGaAlAs epilayers are grown lattice-matched to InP by molecular beam epitaxy with bandgap varying in the energy range 0.8-1.42 eV. It is noted that at room temperature the Schottky characteristics are not observable on these structures where the Al mole fraction is less than 0.42 because of the low metal-semiconductor contact potentials and the dominance of thermionic emission. CV measurement is found to be appropriate for determining the conduction band offsets in samples where the contact is ohmic. This occurs for the case where Al mole fraction is less than 0.12. Also noted is that for an Al mole fraction of 0.23, the bandgap lineup changes from type I to staggered type Il. The variation of Schottky barrier potential is also reported as a function of Al mole fraction in the alloy.

A variety of In1-xGaxAs, In1-yAlyAs and In1-x-yGaxAlyAs films have been grown on InP by molecular beam epitaxy. A comprehensive characterization was performed using Raman scattering, photoluminescence (PL), Fourier transform infrared (FTIR) spectroscopy and double crystal X-ray diffraction on these ternary and quaternary heterostructures with different compositions and growth conditions. The lattice matched and mismatched structures are studied. Our analyses show that the interface mismatch exerts an important influence on the optical properties of these heterostructures, and conversely that Raman, PL and FTIR can be used to probe the interface mismatch nondestructively.

A variety of III-V quaternary ln/sub 1-x-y/Ga/sub x/Al/sub y/As films, for use of 0.8-1.6 /spl mu/m emission optoelectronic devices, have been grown on InP by molecular beam epitaxy (MBE). A comprehensive characterization was performed using double crystal X-ray diffraction (DCXRD), Raman scattering, Fourier transform infrared (FTIR) spectroscopy, photoluminescence (PL), on these heterostructures with different compositions and growth conditions. The lattice matched and mismatched structures are studied. Our analyses show that the interface mismatch exerts an important influence on the optical properties of these heterostructures, and conversely that Raman, PL and FTIR which are powerful nondestructive tools, can be used to probe the interface mismatch.