Dislocation generation of GaAs on Si in the cooling stage

Abstract

Articles you may be interested inCritical size for the generation of misfit dislocations and their effects on electronic properties in GaAs nanosheets on Si substrate

Direct-bonded GaAs∕InGaAs tandem solar cell

“…Most current compound semiconductor solar cell design approaches are focused on either lattice-matched designs or metamorphic growth ͑i.e., growth with dislocations to accommodate subcell lattice mismatch͒, which inevitably results in less design flexibility or lower material quality than is desirable. 2,3 An alternative approach is to employ direct-bonded interconnects between subcells of a multijunction cell, which enables dislocationfree active regions by confining the defect network needed for lattice mismatch accommodation to tunnel junction interfaces. [4][5][6][7][8] We report here a direct-bond interconnected multijunction solar cell, a two-terminal monolithic GaAs/ InGaAs two-junction cell, to demonstrate a proof of principle for the viability of direct wafer bonding for solar cell applications.…”

A Repeatable Epitaxial Lift‐Off Process from a Single GaAs Substrate for Low‐Cost and High‐Efficiency III‐V Solar Cells

“…Therefore, GaAs epilayers grown directly on Si substrates show high dislocation densities, with the dislocations acting as recombination centers in the solar cells. [2][3][4][5] These undesirable dislocations adversely affect the effi ciency of the solar cell. Wafer reuse method is based on the epitaxial lift-off (ELO) technique in which the device layer is separated from the GaAs substrate by using hydrofl uoric acid (HF) to selectively etch an AlAs sacrifi cial layer inserted between the device layer and the substrate.…”

Development of new materials for solar cells in Nagoya Institute of Technology

“…Although the dislocation density in GaAs layer at the crystal growth temperature can be reduced to 10 4 cm K2 by a few cycles of TCA, the difference in thermal expansion coefficients between GaAs and Si induces very high stress in GaAs layer during the cooling process down to room temperature, and a lot of dislocations are introduced to relieve the stress [3]. More than 10 6 cm K2 dislocations act as minority carrier traps and decline the solar cell performance.…”

“…Carbon is also one of the group IV elements and amorphous C (a-C) is expected to behave like a-Si if it is properly prepared. The atomic bond between two Si atoms is sp 3 bond and Si crystallizes into diamond structure. On the other hand, the sp 2 bond is more likely realized between two C atoms which usually form graphite, or sometimes fullerenes, nano-tubes and so on.…”

“…H 2 , CH 4 and 1% trimethylboron (TMB) in H 2 were used as the sources and the flow rates were maintained at 300, 10 and 40 sccm, respectively. The RF power was 300 W (0.87 W/cm 3 ) and the duration of deposition was 1 h. The chamber pressure was controlled to keep the CH 4 partial pressure as P CH4 Z6 Pa [13].…”