Magneto-photoluminescence spectra of GaP/AlP short-period superlattices in high magnetic fields and uniaxial pressures

Abstract

A GaP/AlP multiple-superlattice (SL) containing four kinds of (GaP) m /(AlP) n SLs with different periodicity, (m,n)=(4,4), (5,4), (6,4), (7,4) was grown on a GaP (1 0 0) substrate by means of gas source molecular beam epitaxy. A clamp cell for generating uniaxial pressure was developed allowing an optical measurement in pulsed high magnetic field. We measured magneto-PL spectra in high magnetic fields up to 40 T and uniaxial pressure up to 0.5 GPa and found an intensity enhancement of the PL originating from the (4,4) SL, associated with the indirect to pseudo-direct band-gap transition. The magnetic field dependence at 0.5 GPa is slightly changed from that at atmospheric pressure: the decrease of the PL intensity with increasing magnetic field perpendicular to the SL layer becomes small. This feature indicates that the magnetic field dependence of PL deeply concerns the exciton recombination at the hetero-interfaces.