High Quality p+-n+-GaAs Tunnel Junction Diode Grown by Atmospheric Pressure Metalorganic Vapour Phase Epitaxy

Abstract

We report the growth of a p + -n + -GaAs tunnel diode by atmospheric pressure metalorganic vapour phase epitaxy (MOVPE), using carbon (C) and silicon (Si) as p-type and n-type dopants, respectively. The more efficient incorporation of silicon on donor sites and carbon on acceptor sites, results in a tunnel junction with peak current density up to 50 Acm --2 , and peak-to-valley current ratio up to 20 at room temperature. This represents the best result ever reported for a GaAs tunnel diode by MOVPE. The calculated theoretical peak current density agrees substantially with our experimental and reported results.

GaAs tunnel junction grown using tellurium and magnesium as dopants by solid-state molecular beam epitaxy

“…For a good tunnel junction, high doping levels and abrupt doping profiles are required on both sides of the junction. 5) MBE, with its low growth temperature, excellent thickness control, and capability to provide abrupt profiles at high doping levels, is an attractive method for producing high-quality tunnel junctions that are suitable for solar cells. 6) Recently, a high-efficiency GaAs single junction solar cell was realized through MBE by our research group; 7) however, for dualjunction GaInP/GaAs solar cells, poor performance under high concentration (>100 suns) was observed, the cell current exceeded the maximum tunneling current of the tunnel junction, and a dip appeared.…”

Sidewall GaAs tunnel junctions fabricated using molecular layer epitaxy

“…They had the J p values of only 10-1000 A cm −2 or less for the tunnel junctions fabricated by molecular beam epitaxy (MBE) [6,7,10,13], metal-organic vapour phase epitaxy (MOVPE) [8,9] and metal-organic chemical vapour deposition (MOCVD) [14,15]. We have achieved the fabrication of a sidewall GaAs tunnel junction with a record J p of 35 000 A cm −2 [11,12].…”

“…Later, tunnel junctions have been fabricated using Si [2,3], Si/SiGe [4,5], GaAs [6][7][8][9][10][11][12][13][14][15], InAs/Si [16], GaInAs/GaInNAs [17], InP/InGaAs [18], GaAsSb/InGaAs [19] and InAsP/GaAsP [20]. These tunnel junctions found numerous applications.…”

Tunnel Junctions for III-V Multijunction Solar Cells Review

“…Subsequent work on GaAs/GaAs TJs was aimed largely at understanding the junctions since a GaAs homo-junction could be more easily modeled. Most [6,9,10], though not all [8], of the reports on modeling concluded that direct tunneling (particularly if bandgap narrowing effects were added) adequately explained the tunneling currents observed. This discrepancy was resolved when it was shown [48] that the current in lower doped structures could be explained by direct tunneling if band coupling (mixing) effects were included.…”

“…Some of the experimental data contain fairly high valley currents which almost all models regard as coming from trap assisted tunneling effects. However, a recent study of GaAs/GaAs tunnel diodes [6] which used band gap narrowing data from photoluminescence as well as the methodology used for the initial AlGaAs/InGaP analyses [9,44] concluded that band to band tunneling will account for the current when the effective tunneling barrier thickness of the depletion layer is properly accounted for. It is also worth noting that the temperature dependence of the peak current as discussed in [28] is not straightforward in other systems.…”