Comparing retention and recombination of electrically injected carriers in Si quantum dots embedded in Si-rich SiN_x films

Abstract

Carrier retention and recombination in Si quantum dots (Si-QDs) embedded SiNx light emitting diode with dark-yellow emission of 93 nW and linear P-I slope of 1.2 mW/A at 80 μA bias are compared. The capacitance-voltage hysteresis of <0.5 V reveals low carrier density per Si-QD, and the 1 ms charge retention concludes only 4% carrier retention within ms time. The fast radiative recombination with electroluminescent (EL) response is shorter than the charge retention within Si-QDs, elucidating that the low Si-QD/Si3N4 interfacial barrier is not dominant for small EL quantum efficiency. Few injected carriers and Auger effect in Si-QDs fail to promote the external quantum efficiency.