Direct-bonded GaAs∕InGaAs tandem solar cell

Journal of Applied Physics

Atwater

2008

Self Cite

Sulfide-passivated GaAs and InP wafers were directly bonded to explore the efficiency of sulfide passivation on the bonded interfacial properties. We find that the bonded GaAs/InP interfaces after sulfide passivation contain sulfur atoms and a decreased amount of oxide species relative to the pairs bonded after conventional acid treatment; however, the residual sulfur atoms have no effect on the bonding strength. The electrical properties of the bonded p-GaAs/ n-InP heterojunctions were studied for different acceptor concentrations in p-GaAs. A reduced interfacial trap state density enhances the tunnel current flow across the depletion layer in the sulfide-passivated case. A directly bonded tunnel diode with a heavily doped p-GaAs/ n-InP heterojunction was achieved when the wafers were sulfide passivated and then bonded at temperatures as low as 300°C. This sulfide-passivated tunnel diode can be used for fabrication of lattice-mismatched multijunction solar cells in which subcells are integrated via direct bonding.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Improved electrical properties of wafer-bonded p-GaAs/n-InP interfaces with sulfide passivation

Nakayama

Journal of Applied Physics

Atwater

2008

Self Cite

“…2 Additionally, a proposed four-junction solar cell, fabricated by joining subcells of InGaAs and InGaAsP grown on InP with subcells of GaAs and AlInGaP grown on GaAs through a wafer-bonded interconnect, would enable the independent selection of the subcell band gaps for well developed materials grown on lattice matched substrates. 3,4 Substitution of InP / Si substrates for bulk InP in the fabrication of such a four-junction solar cell could significantly reduce the substrate cost, as described below.…”

mentioning

confidence: 99%

High efficiency InGaAs solar cells on Si by InP layer transfer

Zahler

Applied Physics Letters

Ladous

et al. 2007

Self Cite

InP / Si substrates were fabricated through wafer bonding and helium-induced exfoliation of InP, and InGaAs solar cells lattice matched to bulk InP were grown on these substrates using metal-organic chemical-vapor deposition. The photovoltaic characteristics of the InGaAs cells fabricated on the wafer-bonded InP / Si substrates were comparable to those synthesized on commercially available epiready InP substrates, thus providing a demonstration of wafer-bonded InP / Si substrates as an alternative to bulk InP substrates for solar cell applications.

“…In this absence of metal component, there is no concern for absorption loss in the laser cavities. Although direct bonding is generally considered more difficult than oxide-and metal-mediated bonding, we have recently succeeded in GaAs/InP [11] and GaAs/Si [12] direct bonding to obtain highly conductive Ohmic heterojunctions. current density profiles at the MQWs.…”

Section: Overview Of the Structurementioning

confidence: 99%

Novel III-V/Si hybrid laser structures with current injection across conductive wafer-bonded heterointerfaces: A proposal and analysis

IEICE Electron. Express

Iwamoto

Arakawa

2011

Self Cite

Abstract:We propose two novel III-V/Si hybrid laser structures with patterned window arrays in metal thin film wafer-bonding layers. The metal-mediated bonded III-V/Si heterointerface exhibits high electrical and thermal conductivity while allowing optical coupling between the III-V gain layer and the underneath Si waveguide through the openings in the metal bonding layer. We numerically examine the validity of the proposed hybrid laser structures through calculations of their modal propagation loss by metal's absorption and threshold current densities. We also propose another hybrid laser structure utilizing conductive direct semiconductor/semiconductor wafer bonding exploiting a spatial gain profile well overlapped with the waveguide mode and no metal-induced loss relative to those metal-mediated-bonded. All of these three structures have advantages such as spontaneous lateral current confinement and simpler fabrication over conventional oxidemediated-bonded hybrid lasers.