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SEMICONDUCTOR DIGITAL COMPOSITE; SOLAR-CELLS; GAAS; MICROSTRUCTURE;
JUNCTION; ISLANDS; GROWTH; INGAASEngineering; Materials Science; Physics;
Abstract:
We report on recombination diodes containing monolayer depositions of ErAs between highly doped n- and p-layers in the (Al)GaAs and In(Al)GaAs material system. The ErAs material provides metallic states across the band gap of the host semiconductor that act as efficient recombination centers. Both electrons and holes can tunnel into the ErAs, resulting in extremely high tunneling current densities in the tens of kA cm(-2) range. A device resistance area product of 1-2 x 10(-5) Omega cm(2) at low bias (+/- 0.2 V) has been measured. Measurements on In(Al)GaAs and (Al)GaAs diodes will be compared to a simple theoretical model. Low band gap and high (p-) doping levels are identified as key parameters for achieving highest recombination currents. Compared to ErAs-free diodes, ErAs-enhanced recombination diodes provide orders of magnitude higher current densities at both moderate and low forward and reverse bias. This is attributed to the smaller and narrower tunnel barriers from the n- and p- layers into the ErAs compared to tunneling from the n- to the p-side through the whole depletion region.
