Determination of capture barriers of defects for GaAs alloys and transient photo-resistivity spectroscopy

Abstract

Si-doped Ga0.7Al0.3As grown by molecular beam epitaxy (MBE) and undoped Ga0.47Al0.53As grown by chemical beam epitaxy (CBE) have been investigated using a new deep level characterization method-transient photo-resistivity spectroscopy, which we recently developed. This method measures directly the capture process of deep centers. In GaAlAs, apparent capture barrier energy EB = 0.25 eV of DX center was determined and intrinsic capture barrier energy Eσ = 0.16 eV was directly measured. In GaInAs, a defect with capture barrier energy EB = 0.28 eV was observed. The result proved that DX centers capture electron only from band L, belonging to small lattice relaxation model. The theoretical deduction of transient photo-resistivity spectroscopy was improved.