M. Razeghi

Planar monolithic integrated photoreceiver for 1.3–1.55 μm wavelength applications using GaInAs‐GaAs heteroepitaxies

We report the first fabrication of a monolithic integrated circuit consisting of a Ga0.47In0.53As planar photoconductive detector (suitable for 1.3–1.55 μm wavelength optical communication systems) associated with a GaAs field‐effect transistor. The gain, response times, and noise properties of the photoconductive detector and the integrated photoreceiver have been investigated, taking into account particular aspects of the material and integrated circuit structure.

Cyclotron resonance and polaron effects in a two-dimensional electron gas in GaInAs

Abstract Cyclotron resonance results from GaInAs-InP heterojunctions and superlattices and GaInAs-AlInAs heterojunctions in fields up to 18 T are reported. For low frequencies, the effective mass is compared with the predictions of k · p theory, and the resonance linewidth is fitted to finite range scattering theories. At higher frequencies, the linewidth increases dramatically, while the effective mass deviates from its low-frequency value. These effects are attributed to resonant polaron coupling.

Two-dimensional magnetophonon resonance in GaInAs-InP and GaInAs-AlInAs heterojunctions and superlattices

Abstract We report the observation of magnetophonon resonance in GaInAs-InP heterojunctions and measurements of the temperature dependence of the oscillations. A single series of oscillations due to scattering by the “GaAs-like” mode of GaInAs is seen, in contrast to GaInAs-InP superlattices, where scattering from InP phonons is also observed, and GaInAs-AlInAs heterojunctions, where coupling to “InAs-like” modes only is seen. This behaviour is discussed in terms of long-range phonon interactions and interface phonons.

High yield manufacture of very low threshold, high reliability, 1.30-µm buried heterostructure laser diodes grown by metal organic chemical vapor deposition

We report the fabrication of very low threshold buried heterostructure lasers by a two-step MOCVD technique. We show very high yield of fabrication, very high uniformity of the initial characteristics, good reproducibility, and low degradation rate during the aging test.

Low-threshold distributed feedback lasers fabricated on material grown completely by LP-MOCVD

GaInAsP-InP distributed feedback (DFB) lasers emitting at 1.57 μm have been fabricated on material grown completely by low-pressure metalorganic chemical vapor deposition (LP-MOCVD). The CW threshold current of 60 mA and an output power of 6 mW per facet at room temperature have been obtained. The lasing wavelength λ L under CW operation showed a temperature coefficient ( d_{lambdaL}/dT ) of 0.9 A/°C for this DFB laser over the range of 10-90deg C. A stable single longitudinal mode was maintained under high speed pulse modulation up to 500 ps, and sinusoidal modulation at 1 Ghz.

Properties of 2D quantum well lasers

Abstract The lasing characteristics of quantum well and double heterostructure lasers are compared for the GaAs/GaAlAs and GaInAs/InP materials systems. The poorer performance of GaInAs/InP quantum well lasers is shown to be due to carrier heating linked to Auger recombination. However, low-temperature measurements reveal that in other respects these lasers are well behaved.

Frequency shifted polaron coupling in GaInAs heterostructures

Abstract Frequency dependent cyclotron resonance measurements are reported on Ga0.47In0.53Asue5f8InP and Ga0.47In0.53Asue5f8Al0.48In0.52As heterostructures. Discontinuities in the effective mass are observed at two frequencies, due to resonant polaron coupling to the two optic phonon modes in GaInAs. In heterojunctions the coupling occurs at the frequencies of the TO phonons, in contrast to bulk materials, and the relative strength of the coupling to the two modes is different in the two systems. In more lightly doped superlattices the coupling is stronger, leading to larger shifts in the effective mass, and occurs at the LO phonon frequencies. This behaviour is discussed in terms of possible changes in the screening and polarisation of the optic phonon modes.

Thermoelectric power of GaInAs-InP and GaInAs-AlInAs heterojunctions in a magnetic field

Abstract This work reports measurements of the diagonal thermopower in several heterojunctions based on Ga.47In.53As, in high magnetic fields and as a function of temperature. Structures have been studied in which only one or two electric subbands are populated, and in both cases the thermopower oscillations are in phase with the Shubnikov-de Haas oscillations in the resistivity, in accordance with theory. The absolute magnitude of the thermopower is found to be smaller than predicted by theory, and is also highly temperature dependent.

Measurements of thermoelectric power in two-dimensional systems

Abstract The diagonal component of the thermoelectric power in GaInAsue5f8InP, GaInAsue5f8AlInAs and GaAsue5f8GaAlAs heterojunctions and a GaAsue5f8GaAlAs superlattice has been studied as a function of magnetic field and temperature. In high magnetic fields, the thermopower shows oscillations proportional to the resistivity oscillations, including features due to spin splittings and the occupation of two electric subbands. The peak values of the thermopower in the GaAsue5f8GaAlAs superlattice are almost independent of temperature and close to the theoretical predictions. In contrast, the peak thermopowers measured in the heterojunctions are lower than predicted by factors of between 2 and 50, and decrease with increasing temperature.

MOCVD GROWTH FOR HETEROSTRUCTURES AND TWO-DIMENSIONAL ELECTRONIC SYSTEMS.

The LPMOCVD technique has been successfuly used to grow heterojunctions and superlattices of GaxIn1−xAsyP1−y lattice-matched to InP for the complete compositional range between InP (λ = 0.91 μm, Eg = 1.35 eV) and the ternary compound Ga0.47In0.53As (λ= 1.67 μm, Eg = 0.75 eV). We have observed Shubnikov-de Haas oscillations in heterojunctions and superlattices of Ga0.47 In0.53 As-InP and Ga0.25In0.75As0.5 P0.5 - InP showing evidence of two-dimensional behaviour