Photoluminescent properties and optical absorption of AlAs/GaAs disordered superlattices

Abstract

A disordered superlattice, a recently proposed artificially constructed material, is fabricated and photoluminescent properties and optical absorption are investigated. Disorder is intentionally introduced into the period of the superlattice in order to enhance its photoluminescence. The photoluminescent temperature dependences and the optical absorption spectra of Al0.5Ga0.5As bulk alloy, AlAs/GaAs ordered superlattice, and AlAs/GaAs disordered superlattice are studied and compared. The optical absorption spectra suggest that localized states are created in the band tail of the AlAs/GaAs disordered superlattice. The photoluminescence spectra of the disordered superlattice are strongly dependent on the localized states, and the temperature dependence of photoluminescence intensities obeys the same relation IPL∝[1+A exp(T/T0)]−1 as that reported for amorphous semiconductors.

InAlGaAs/InAlAs MQWs on Si Substrate

“…The intensity drops and the emission peak red shifts with decreasing temperature. This phenomenon was first observed in InAlGaAs material by Chua et al [24], associated with multiple competing transitions and exciton localization, caused by disordered alloy atomic arrangement [25]. To further estimate the IQE variations of the QWs, we calculated the emission power by integrating over the PL spectra at different temperatures.…”

Effects of Coulomb interaction in intentionally disordered semiconductor superlattices

“…Here, multiple quantum wells (MQWs) and superlattices (SLs) with intentional vertical disorder appear to be very attractive. GaAs/GaAlAs SLs, first discussed in [1] and realized in [2,3], provide an ideal model system and are now becoming the object of growing interest [4][5][6][7]. In particular, the quasi-one-dimensional transport properties of the highly anisotropic SL systems depend strongly on the localization of electronic states induced by disorder or external fields.…”

“…In the past, most experimental studies were based on optical methods [2][3][4], in particular stationary and time-resolved picosecond luminescence spectroscopy. These experiments provided clear evidence of vertical transport and even made it possible to estimate the temperature dependence of the carrier mobility in the growth direction [8].…”

Time-resolved spectra and kinetics of the exciton photoluminescence in different types of GaAs/AlAs superlattices

“…For fully indirect SLs with ultra-short periods, i.e. with individual layer thicknesses of less than or equal to three monolayers, there are only a few reports on the time evolution of the PL signal [7,19].…”