Influence of defects on elastic gate tunneling currents through ultrathin SiO2gate oxides: predictions from microscopic models

Journal of Applied Physics

Rubel

et al. 2008

Current-voltage characteristics of GaAs tunnel diodes are studied experimentally and theoretically. In theoretical calculations contributions of three different transport mechanisms are considered: direct tunneling processes, nonresonant multiphonon tunneling processes via defects, and resonant tunneling processes through defects. The comparison between theoretical results and experimental data reveals resonant tunneling as the dominant transport mechanism at voltages corresponding to the peak current. At higher voltages this mechanism is replaced by nonresonant tunneling, which is in its turn replaced by over-barrier transport at even larger voltages

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Resonant electron tunneling through defects in GaAs tunnel diodes

Journal of Applied Physics

Rubel

et al. 2008

“…The tunneling current can be conditioned by several possible tunneling mechanisms, [3][4][5][6][7][8][9][10][11][12][13] namely, ͑i͒ direct band-toband tunneling, ͑ii͒ phonon-assisted tunneling through defects, and ͑iii͒ resonant tunneling through defects. For different applied voltages different tunneling mechanisms can be dominant.…”

mentioning

confidence: 99%

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

Applied Physics Letters

Rubel

et al. 2008

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 .

“…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.…”

Section: Introductionmentioning

confidence: 72%

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

J. Phys. D: Appl. Phys.

Stolz

et al. 2009

Interband tunnel diodes are widely used to electrically interconnect the individual subcells in multi-junction solar cells. Tunnel diodes have to operate at high current densities and low voltages, especially when used in concentrator solar cells. They represent one of the most critical elements of multi-junction solar cells and the fluctuations of the peak current in the diodes have an essential impact on the performance and reliability of the devices. Recently we have found that GaAs tunnel diodes exhibit extremely high peak currents that can be explained by resonant tunnelling through defects homogeneously distributed in the junction. Experiments evidence rather large fluctuations of the peak current in the diodes fabricated from the same wafer. It is a challenging task to clarify the reason for such large fluctuations in order to improve the performance of the multi-junction solar cells. In this work we show that the large fluctuations of the peak current in tunnel diodes can be caused by relatively small fluctuations of the dopant concentration. We also show that the fluctuations of the peak current become smaller for deeper energy levels of the defects responsible for the resonant tunnelling.