DETERMINATION OF CAPTURE BARRIERS OF DEFECTS FOR GaAs ALLOYS AND TRANSIENT PHOTO-RESISTIVITY SPECTROSCOPY

Si-doped Ga_0.7Al_0.3As grown by molecular beam epitaxy (MBE) and undoped Ga_0.47Al_0.53As 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 E_B= 0.25eV of DX center was determined and intrinasic capture barrier energy E_\sigma = 0.16eV was directly measured. In GaInAs, a defect with capture barier energy E_B= 0.2BeV 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.