Depth profile of acceptor concentration in InGaN/GaN multiple quantum wells

Zn contamination of InGaN/GaN multiple quantum well (MQW) structure from unknown source is found. A model describing concentration profile of Zn acceptor impurity in InGaN/GaN MQW structure is introduced and compared to measured values. The model is based on difference among the formation energies of acceptors in the InGaN quantum wells. A nice correlation of the model and experimental data helps to reveal origin of Zn impurity in InGaN quantum wells. Proposed methodology can be applied to different acceptor-like defects and shine light the upon enigma of high defect concentration in the bottom quantum wells grown atop the n-type buffer layer. •Unusual Zn impurity distribution among InGaN/GaN QWs is observed.•Model based on different formation energies for acceptor defect in QWs is proposed.•From model results, the source of Zn contamination is most probably triethylgallium precursor.