Photoluminescence Wavelength Dependence on Layer Structure of GaP/AlP Modulated Superlattices

Abstract

In the (GaP) m 1 (AlP) n 1 (GaP) m 2 (AlP) n 2 ( m = m 1+ m 2, n = n 1+ n 2, m 1≥ m 2, n 1≥ n 2) modulated superlattices (SLs) grown on (001) GaP substrates by gas-source molecular beam epitaxy, a blue shift of 4.2 K photoluminescence (PL) peak is observed with decreasing the wide periods of ( m 1+ n 1). It is suggested that holes and electrons are localized in the wide GaP ( m 1) and AlP ( n 1) layers, respectively, and that the PL peak wavelength is mainly determined by the wide SL periods of ( m 1+ n 1). This suggestion is supported by the observed PL peak wavelengths for the {(GaP) 11 (AlP) 3 } j {(GaP) 2 (AlP) 2 } 2 and (GaP) 5 (AlP) 5 {(GaP) 2 (AlP) 2 } k modulated SLs, where the wavelengths are almost independent of j and k .