Fast capacitance transient appartus: Application to ZnO and O centers in GaP <i>p-n</i> junctions

TLDR

The authors introduce new capacitance transient techniques and apparatus that extend measurement to intermediate‑depth impurity and defect states and apply them to determine electron‑capture cross sections and concentrations of isolated oxygen donors and ZnO complex luminescence centers in p‑type Zn‑ and O‑doped GaP. The method employs the developed capacitance transient apparatus to measure electron‑capture cross sections and concentrations of these defect states in the GaP junction. The apparatus enhances capacitance transient studies of nonradiative recombination, confirming donor‑acceptor pairing theory, showing isolated O donors are negligible recombination centers, and demonstrating that the junction electric field markedly increases the thermal emission rate from ZnO centers.

Abstract

New techniques and apparatus are presented which overcome some of the limitations of previous capacitance transient techniques and extend the useful range of capacitance transient measurements to intermediate depth impurity and defect states in semiconductors. This development greatly enhances the usefulness of capacitance techniques as a tool to study nonradiative recombination. These techniques and apparatus are used here to measure the electron-capture cross sections and concentrations of isolated oxygen donors and ZnO complex luminescence centers in p-type Zn- and O-doped GaP. These results agree with the donor-acceptor pairing theory and with the conclusion of previous capacitance measurements that the ioslated O donor is of negligible importance as a recombination center in these samples. Data is also presented which shows the effect of the junction electric field in greatly enhancing the thermal emission rate of electrons trapped in ZnO centers.