Efficient above-band-gap light emission in germanium

We report, all above-band-gap radiative transition ill the photoluminescence spectra of single crystalline Ge in the temperature range of 20-296 K. The temperature-independence of the peak position at similar to 0.74 eV is remarkably different front the behavior of direct and indirect gap transitions in Ge. This transition is observed in n-type, p-type; and intrinsic single crystal Ge alike; and its intensity decreases with the increase of temperature witty a small activation energy of 56 meV. Some aspects of the transition are analogous to III-V semiconductors with dilute nitrogen doping; which suggests drat tire: origin could be related to all isoelectronic defect.