Bulk and interface deep levels in InGaP/GaAs heterostructures grown by tertiarybutylphosphine-based gas source molecular beam epitaxy

InGaP/GaAs heterostructures were grown by gas source molecular beam epitaxy (GSMBE) using tertiarybutylphosphine (TBP), and their bulk and interface d eep levels were studied by deep level transient spectroscopy (DLTS), photol uminescence (PL), and cathodoluminescence (CL) techniques. Five bulk deep l evels related to phosphorus vacancies and their complexes were detected by DLTS. They could be almost completely removed under a TBP flow rate higher than 4-5 seem, accompanied by a marked increase of the bulk band edge PL in tensity. On the other hand, InGaP/GaAs heterostructures grown under high TB P flow rates showed anomalous PL and CL peaks near 1.7 eV. CL study perform ed by changing the acceleration voltage showed that these peaks were hetero interface related, most likely due to phosphorus vacancies near interfaces. InGaP/GaAs quantum wells (QW) without such peaks and with intense QW emiss ion were successfully formed by avoiding phosphorous vacancy formation thro ugh elimination of growth interruption.