Resonant tunneling as a dominant transport mechanism in n-GaAs∕p-GaAs tunnel diodes

Abstract

Current-voltage characteristics of Ga 0.99 In 0.01 As tunnel diodes are studied experimentally and theoretically. Three possible tunneling mechanisms are considered: direct band-to-band tunneling, phonon-assisted tunneling through defects, and resonant tunneling through defects. Comparison between theoretical results and experimental data reveals resonant tunneling through oxygen-related defects as the dominant transport mechanism at voltages corresponding to the peak current in diodes with doping level about 10 19 cm −3 .

Analytical theory for favorable defects in tunnel diodes

“…5,6 The value of the transmission coefficient in the case of resonant tunneling through defects is determined by the capture cross section and the position of the energy level of the defects. One of the important demands in these devices is a low electrical resistivity which results from an efficient tunneling of charge carriers through the depletion layer of the diode.…”

Fluctuations of the peak current of tunnel diodes in multi-junction solar cells

“…Besides optical transparency, the evident requirement to TDs is the low resistivity. In our previous experimental studies on n-GaAs/p-GaAs TDs [3,4] very high current densities of 20-25 A cm −2 were achieved at low applied voltages (∼0.1 V). According to our theoretical calculations [3,4], neither the direct tunnelling of electrons from the conduction band of the n-type part of TDs into the valence band of the p-type part nor the defect-assisted multiphonon tunnelling [5][6][7] can provide a satisfactory explanation for the experimental data.…”

“…In our previous experimental studies on n-GaAs/p-GaAs TDs [3,4] very high current densities of 20-25 A cm −2 were achieved at low applied voltages (∼0.1 V). According to our theoretical calculations [3,4], neither the direct tunnelling of electrons from the conduction band of the n-type part of TDs into the valence band of the p-type part nor the defect-assisted multiphonon tunnelling [5][6][7] can provide a satisfactory explanation for the experimental data. Instead, the resonant tunnelling [8][9][10] through defects homogeneously distributed within the depletion layer of the tunnel junction is the dominant transport mechanism responsible for the high currents at low applied voltages.…”

Type II heterojunction tunnel diodes based on GaAs for multi-junction solar cells: Fabrication, characterization and simulation

“…As pointed out in [3], the physical nature of the transport mechanisms in TJs has been a subject of debate in the literature. Recent literature suspect that trap related mechanisms could be the predominant tunneling effect in such devices [4]. However, we presented in previous work [5] a direct interband tunneling model model able to quantify the current-voltage characteristics of GaAs tunnel junction from reliable materials data when the coupling between the Conduction Band (CB) and the Light-Holes Valence Band (LH-VB) is carefully taken into account by the Flitener's formula for the tunneling probability evaluation.…”