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The temperature dependence of the intensity of the G vibronic band is reported. Absorption data are given for the range 2 to 200 K, and luminescence data for the range 2 to 90 K. The data show that the molecular structure of the G centre is invariant in these ranges. From 2 to 30 K the luminescence intensity undergoes a specimen-dependent growth. We suggest the growth is caused by the thermal ionisation of competing shallow exciton traps. Above 30 K the luminescence intensity undergoes an intrinsic decrease, and is quenched to 0.2% of the low-temperature value by 77 K.

We report 77-K electroluminescence from an irradiated carbon-rich silicon diode that has an internal quantum efficiency more than 103 times higher than that of band-to-band recombination in an unirradiated, but otherwise identical diode. This is achieved by creating optically active Cs-SiI-Cs complexes with room-temperature electron bombardment at an energy between the displacement thresholds for single vacancy and divacancy formation. Under these irradiation conditions, it is possible to create a high concentration of radiative defects without gross degradation of the diode’s electrical characteristics. The technique could provide very large scale integration-compatible silicon light-emitting diodes for 1.3–1.6 μm all-silicon integrated optics.

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