Low Resistance Tunnel Junctions for Efficient Electrically Pumped Nanolasers

Extremely compact nanoscale devices such as electrically pumped nanolasers are difficult to operate at room temperature due to the high electrical resistance inherent to small cavities. As a consequence, large voltages are necessary to reach the lasing threshold, which generates heat and reduces device efficiency. The poor heat sinking of small devices makes matters worse, dramatically reducing the laser efficiency. Instead of looking for solutions to dissipate heat from small structures more efficiently, designing nanolasers to produce less heat in the first place is an important goal. Here we propose and theoretically analyze the effect of adding an InGaAsP tunnel junction for efficient carrier injection in metallo-dielectric nanolasers. With our theoretical model we show that the device resistance is reduced by a factor of similar to 6.5. The applied voltage at the room temperature lasing threshold is reduced from 3.05 to 1.35 V, a reduction of 69% in heat generation, whereas the Q-factor and gain threshold of the cavity are not degraded.