Correlation of optical properties and interface morphology in type-II semiconductor heterostructures

Abstract

(Ga,In)As/GaAs/Ga(As,Sb) and (Ga,In)As/GaAs/Ga(N,As) type-II double quantum well heterostructures have been grown by metal-organic vapor phase epitaxy. A growth interruption procedure was used to intentionally modify the morphology of the internal interfaces. The heterostructures were investigated using continuous wave and time-resolved photoluminescence as well as optical pump–optical probe spectroscopy. We find a correlation between the interface morphology and optical and kinetic properties. A growth interruption of about 120 s yielded substantially smoother interfaces both on vertical as well as lateral length scales. On the other hand a considerably enhanced type-II recombination time as well as a longer electron tunneling time are observed. We attribute this to a reduced interface localization in case of smoother interfaces.

Preface: fresh perspectives on internal interfaces

“…Optical spectroscopies such as optical second-harmonic generation (SHG) [22,26] differential reflectance spectroscopy (DRS) [16] or time-resolved photoluminescence (TR-PL) [14] combine the large penetration depth of light with interfacespecific symmetry properties or interface-specific optical transitions. In combination with pump-probe techniques, they are used to study the dynamics of ultrafast processes at interfaces in the time domain [12,14,23,24,26].…”

“…Organic molecules are also studied on graphite and graphene [8,19] and are covalently attached to thin oxide films [3] or Si surfaces [5]. Several other studies focus on interfaces between inorganic semiconductors [22][23][24][25][26][27], including buried GaP/Si hetero-interfaces [22,24,27]. The growing interest in interfaces of 2D materials such as graphene [19] and transition-metal dichalcogenites [28,29] is also documented in this collection.…”

“…Ishioka et al used optical pump-probe measurements to investigate the ultrafast electron-phonon coupling dynamics at GaP/Si interfaces and found that the GaP phonon-plasmon coupling depends on the GaP layer thickness due to the 2D confinement of the plasmons in the thinner GaP layers [24]. Time-resolved PL as well as optical pump-optical probe spectroscopy of (Ga,In) As/GaAs/Ga(As,Sb) and other type-II double quantum well heterostructures revealed correlation between the interface morphology and optical and kinetic properties [23]. Diode rectification behaviour of a 2D p-n interface made of few-layer GaSe and bilayer MoS 2 was found by Rahaman et al [29] through current sensing atomic force microscopy.…”

The influence of growth interruption on the luminescence properties of Ga(As,Sb)-based type II heterostructures

“…In a previous publication we could show that one can improve the type II photoluminescence efficiency by smoothening the interface of (Ga,In)As [12]. As extremely sensitive probe the type II recombination has been used of (Ga,In)As/GaAs/Ga(As,Sb) double quantum well (DQW) heterostructures.…”