Selectively excited photoluminescence of GaAs1−xSbx/GaAs single quantum wells

Abstract

GaAsSb/GaAs single quantum wells grown by molecular-beam epitaxy are studied by selectively excited photoluminescence measurements. We have simultaneously observed the photoluminescence (PL) from both type-I and type-II transitions in the samples. The two transitions exhibit different PL behavior under different excitation energies. As expected, the peak energy of the type-I emission remains constant in the entire excitation energy range we used, while the type-II transition shows a significant blueshift with increasing excitation energy. The observed blueshift can be well explained by an electron–hole charge separation model at interface. This result, along with the excitation-power-dependent PL and the measured longer carrier decay time, provides more direct information on the type-II nature of the band alignment in GaAsSb/GaAs quantum well structures.

Carrier dynamics between delocalized and localized states in type-II GaAsSb/GaAs quantum wells

“…Previous experimental results in the literature 3,4 do not provide any detailed picture of the mechanisms for carrier relaxation. The main goal of this letter is to use timeresolved photoluminescence ͑TRPL͒ to which may finally bring some understanding into the carrier relaxation processes in the type-II GaAsSb/GaAs quantum wells.…”

“…The main goal of this letter is to use timeresolved photoluminescence ͑TRPL͒ to which may finally bring some understanding into the carrier relaxation processes in the type-II GaAsSb/GaAs quantum wells. We show a strong influence of the dynamic band bending effect 4,12,13 on the observed PL kinetics and point out the important role of carrier trapping by localized states, which affects the relaxation dynamics in the structure. Eventually, we propose a carrier relaxation scenario where the carrier transfer between delocalized and localized states plays an important role.…”

“…One of the most important features is the possibility to tune the conduction lineup from type-I to type-II band alignment. [1][2][3][4][5][6] While the type-I structures found their application in light emitting devices, the unique properties of type-II GaAsSb/GaAs heterostructures can result in substantial improvements in the performance of near infrared detectors and heterojunction bipolar transistors. 7,8 Type-II GaAsSb/GaAs QWs [9][10][11] have also been used in the development of laser diodes emitting at 1.3 m, which may provide an interesting alternative to GaAs-based telecommunications lasers based on highly strained InGaAs/GaAs QWs, dilute nitride QWs, or InAs quantum dots.…”

Molecular beam epitaxy growth and photoluminescence study of room temperature 1.31μm (InyGa1−yAs/GaAs1−x Sbx)/GaAs bilayer quantum wells

“…Since photo-generated electrons are confined separately in InGaAs layer and holes in the GaAsSb layer, the Columbu interaction between electrons and holes sets up an electric field forming a triangle potential well at the interfaces. With increasing excitation power intensity, the band filling effects and charge transfer cause a band bending and thus lead to inflexion of the PL energy shifts, which is similar to GaAsSb/ GaAs and GaInP/GaAs heterostructures [16].…”

Sidewall GaAs tunnel junctions fabricated using molecular layer epitaxy

“…GaAsSb and GaSb growth are also used for manufacturing photoconductive THz emitters [118][119][120], THz laser [121] and double HBT structure [122]. GaAsSb/GaAs quantum wells have attracted attention for their potential applications in electronic and optoelectronic devices, and these structures have been fabricated and evaluated in several reports [123][124][125][126][127][128][129][130][131]. In addition, an undoped GaAsSb quantum well was grown by MLE on undoped semi-insulating (100), (111)A, (111)B and (110) GaAs substrates using trimethylantimonide [132].…”