Optical studies of type-I GaAs1−xSbx/GaAs multiple quantum well structures

Abstract

Temperature dependent surface photovoltage spectra of type I GaAs1−xSbx/GaAs multiple quantum well structures J. Appl. Phys. 113, 073702 (2013); 10.1063/1.4792065 Photoreflectance and surface photovoltage spectroscopy of beryllium-doped Ga As ∕ Al As multiple quantum wells J. Appl. Phys. 98, 023508 (2005); 10.1063/1.1978970 Temperature dependent photoreflectance and photoluminescence characterization of GaInNAs ∕ GaAs single quantum well structures J. Appl. Phys. 96, 6298 (2004); 10.1063/1.1805724Modeling and analysis of photomodulated reflectance and double crystal x-ray diffraction measurements of tensilely strained InGaAs/InGaAsP quantum well structuresWe present photoreflectance ͑PR͒ and surface photovoltage spectroscopy ͑SPS͒ studies of GaAs 1−x Sb x / GaAs multiple quantum well structures with fundamental transition close to 1.3 m. These two optical diagnostic tools are powerful supplementary techniques in the investigations of complicated quantum systems. PR gives detailed information about the heavy-holes related transitions, while SPS contains additional information concerning light-holes related ones. The comparison of experimental data and theoretical analysis based on the envelope function approximation, including strain and exciton binding energy, allows us to identify the observed PR and SPS features. The results point to the existence of weak type-I band alignment in samples being studied, and the Sb content dependent of conduction band offset is found to agree well with that reported by Wang et al. ͓Phys. Rev. B 70, 195339 ͑2004͔͒.

Surface photovoltage and modulation spectroscopy of E− and E+ transitions in GaNAs layers

“…The sample is mounted in a capacitor like sample holder on a bottom electrode (i.e., a copper plate) and covered by a top electrode (i.e., a metal grid). The induced SPV signal on the metal grid was measured with a copper bottom as the ground electrode, using a buffer circuit and a lock-in amplifier [26].…”

“…It is a contactless and nondestructive method which can provide information for both the optical absorption transitions and the electronic transport in bulk materials and nanostructures even at room temperature. Recently, SPV was extensively applied to study the band structure of low dimensional heterostructures [21][22][23][24][25][26]. Also dilute nitrides were investigated by this technique [27][28][29] but the observation of E + transition in SPV spectra was not reported so far for these materials.…”

Temperature dependent surface photovoltage spectra of type I GaAs1−xSbx/GaAs multiple quantum well structures

“…The samples under consideration are of type I band alignment with weak confinement for electrons from our prior investigation. 7 If we focus on one particular spectrum, we can observe two main features in the energy range below 1.35 eV. The lower energy feature is related to the sum of two optical transitions: (i) the fundamental transition which has its origin from the transition between the first heavy-hole state in the valence band and the first electronic state in the conduction band (1hh-1e) and (ii) a feature located slightly higher in energy and can be attributed to heavy-hole to conduction band transition (1hhcb).…”

Optical Transitions between Confined and Unconfined States in p-Type Asymmetric GaAs/InGaAs/AlGaAs QW Structures

“…Another confirmation of our identification is that there is no evidence of that kind of features in PR spectra. This is because transitions between confined and unconfined states should not be observed in PR [5].…”

“…In SPS measurement, the contact potential difference between the sample and a reference grid electrode was measured in a capacitive manner as a function of the photon energy of the probe beam [4,5]. The light from a 250 W tungstenhalogen lamp was passed through a 0.32 m Jobin-Yvon monochromator, chopped at 180 Hz and focused onto the sample.…”