Optical investigation of the band structure of InAs/GaAs short-period superlattices

Abstract

We discuss optical data obtained on (InAs/GaAs)-InGaAlAs multiquantum well structures grown by molecular beam epitaxy. The combined use of photoluminescence and photoluminescence excitation to study such structures is an efficient test of the quality of the highly strained InAs/GaAs ordered alloy, which is used as the well material. The electron effective mass and the lifting of the valence-band degeneracy in InAs/GaAs short-period superlattices are obtained experimentally for the first time.

(InAs)1/(GaAs)n Superlattice Quantum Well Lasers

“…85 As layer, 100A thick n-GaAs spacer layer, 6periol n-doped (InAs) 1 /(GaAs) 4 11.0. layer where x and p varied from 0.15 to 0.6 and 1xl0 16 to 5x10lt, respectively, a 1.6jm thick p-Al0. 6 Ga0. 4 As top cladding layer, and 0.2rpm thick p+-GaAs contact layer.…”

“…2 Gao.SAs/GaAs quantum-well (QW) lasers have been used to pump Erbium Doped Fiber Amplifiers for use in opto-electronic communication systems. These InGaAs/GaAs Q-W lasers grown as graded index separate confinement heterostructures (GRINSCH) emit at 980 nm and have exhibited low threshold current densities, high electrical to optical power conversion efficiencies, low noise, and low temperature sensitivities [1-31. Recently there has been much attention toward the growth and fabrication of devices containing short period superlattices of (InAs)m/(GaAs)n or (GaAs)m/(AlAs)n compositions [4][5][6][7][8][9]. Indeed the growth of inverted MODFET structures using a (GaAs)/(AlAs) superlattice barrier in place of an AlGaAs random alloy exhibited an increase in low temperature mobility due to reductions in the number of impurities and interface roughness [7].…”

Low-Temperature Growth of InGaAs Quantum Wells Using Migration-Enhanced Epitaxy

“…The thickness of the QW determines the quantum confinement strength and electronic/optical properties, depending on the application requirements. The random arrangement of In and Ga in InGaAs leads to alloy scattering [15,16]. The sharpness of the interfaces between the QWs and the barrier layers are important for minimizing defect states and optimizing carrier mobility.…”

“…The electron mobility of the InGaAs QWs is limited not only by polar optical phonon scattering and ionizing impurity scattering, but also by disorder scattering due to the random arrangement of atoms such as In and Ga. This disorder scattering greatly reduces the electron mobility [15,16].…”

“…Through avoiding this randomness, alloy scattering is mitigated by using InAs/GaAs superlattices instead of InGaAs alloys [16,18]. These SPSs, as ordered replacements for InGaAs random alloys, may help to reduce the effects of alloy scattering in InGaAs-based high-speed electronic devices [15,16,19]. Andre et al used metal-organic vapor phase epitaxy (MOVPE) to grow (InAs)n(GaAs)n short-period superlattices, attaining mobilities slightly above those of InGaAs [19].…”