Persistent Photoconductivity (PPC) and Related Deep Metastable Center in MBE Grown p-Type ZnMgSSe

Abstract
A persistent-photoconductivity (PPC) effect and the related deep metastable centers have been investigated for a p-type ZnMgSSe quaternary system grown by molecular beam epitaxy. A low temperature photo-excitation revealed a marked PPC effect in nitrogen doped p-type Zn1-x MgxSySe1-y (0.05<xyT) = τ0 exp (-490±50 meV/k T). It is also confirmed that the low-temperature photo-excitation has caused a new deep metastable hole trap center with thermal hole activation energy of 650 meV. This metastable deep center is evidenced to be responsible for the observed PPC effect.