Abstract
We report the performance enhancement of a molecular beam epitaxy grown GaAs tunnel diode embedded with InAs quantum dots (QDs) for tandem solar cell application, and characterization of tunnel diodes embedded with InAs QDs grown with different growth parameters. Prior to the growth and fabrication of the tunnel diode, InAs QDs were grown under different growth durations and temperatures. The InAs QD samples grown in a temperature range from 480 to 520 °C for a duration of 32 s showed the highest areal fill fraction by InAs QDs. Tunnel diodes embedded with InAs QDs that were grown at various growth conditions were fabricated and characterized. We found that the tunnel diode embedded with InAs QD grown at 520 °C showed the highest peak tunnel current density among all the samples. The enhanced performance of the InAs QD embedded tunnel diode is attributed to the large areal fill fraction produced by the presence of large InAs QDs having high density, which are formed at sufficiently high growth temperature and long growth duration.