Identification and removal of deep levels in InGaP/GaAs heterostructures grown by TBP-based GSMBE

From PL, CL and DLTS measurements, several bulk and interface deep levels were detected in the InGaP epitaxial layers and the InGaP/GaAs quantum wells (QWs) grown by TBP-based GSMBE. These bulk deep levels were almost completely removed by the growth under large TBP flow rate. These bulk deep levels seem to be related to phosphorous vacancy (V_p) or V_p-related complex. On the other hand, InGaP-on-GaAs hetero-interface formed with finite growth interruption exhibited anomalous PL emission at around 1.7 eV. A defect due to strained InGaAsP interlayer at the InGaP-on-GaAs interface produced by the growth interruption is likely to be responsible for the anomalous emission. Anomalous emission was suppressed drastically by the growth without interruption. Intense and narrow PL emissions due to the QWs themselves were observed for the QWs grown without growth interruption