摘要：

Photoluminescence (PL) studies of nitrogen doped ZnSe epilayers grown by molecular beam epitaxy have been performed as a function of excitation wavelength, power density, and temperature. The broad emission from heavily doped ZnSe:N is composed of two distinct bands which we label as N I and N II . The dominant band N I appears at 2.54 eV, while the N II band position is sensitive to excitation power and occurs between 2.55 and 2.61 eV. The N I emission energy is insensitive to incident power or temperature over the ranges studied. Further, a 69 meV localized phonon of the N I band is observed. We propose that the N I band is related to transitions within a (V se +-Zn-N se -)0 close-associate pair. The N II band displays characteristics consistent with the conventional donor acceptor pair model. A third band N III at 2.65 eV is observed under high-power pulsed excitation. Previous studies of heavily doped ZnSe:N had suggested that the broad emission band was described by a modified donor-acceptor pair model. Our PL study does not support this previous model. In addition, our data suggests that singly ionized selenium vacancy complexes form in heavily doped ZnSe:N and play a role in compensation.

展开