Capacitance spectroscopy of CdTe self-assembled quantum dots embedded in ZnTe matrix

Abstract

Abstract In this study the capacitance–voltage (C–V) and deep level transient spectroscopy (DLTS) measurements have been performed on ZnTe (p-type)–Ti/Au Schottky diodes containing one layer of CdTe self-assembled quantum dots (SAQDs). The reference sample was the ZnTe–Ti/Au diode without dots. Both samples were grown by molecular beam epitaxy technique. The dots were formed during the Stranski–Krastanov growth mode. DLTS measurements for the sample with QDs reveal the presence of two hole-related signals with thermal activation energies equal to E H1 =0.2 eV and E H2 =0.4 eV. For the reference ZnTe–Ti/Au diode only the H2 signal is observed. It may be concluded that the H1=0.2 eV level can be assigned to the hole emission from the QDs. The 0.4 eV trap is attributed to the ZnTe bulk material.