Lateral quantum well wires fabricated by selective metalorganic chemical vapor deposition

Abstract

GaAs quantum wires of a new type are fabricated on {1̄10} crystallographic facets perpendicular to the (1̄1̄1̄)B substrates by selective area growth using metalorganic chemical vapor deposition. First, rectangular-shaped AlGaAs layers are grown on a SiO2 stripe-masked GaAs (1̄1̄1̄)B substrate at a high growth temperature. Next, n-AlGaAs/GaAs modulation-doped structures are laterally grown on {1̄10} sidewalls at a low growth temperature. The channel width of the one-dimensional electron gas can be exactly controlled by the thickness of the first rectangular AlGaAs layer. The existence of the quasi-one-dimensional electron gas on {1̄10} sidewalls is confirmed by the orientation dependence of the Shubnikov-de Hass oscillations. The advantage of this quantum wire structure is that there is no size fluctuation which is usually present when dry etching processes are used. Other applications of this selective growth on masked substrates, such as lateral superlattices, are also discussed.

Area selective epitaxy of GaAs with AlGaAs native oxide mask by molecular beam epitaxy

“…Recently, nanostructures such as quantum dots [1,2] and quantum wires [3,4] have been fabricated by combining the bottom-up crystal growth techniques and top-down microand nanofabrication techniques by using molecular beam epitaxy (MBE) and metal organic vapor phase epitaxy (MOVPE). Among these, area selective epitaxy (ASE) is one of the most promising methods to fabricate semiconductor micro-and nanostructures because it produces less damage in the substrate than the direct machining techniques such as reactive ion etching (RIE) and focused ion beam implantation (FIB) [5,6].…”

Advances in steep-slope tunnel FETs

“…In this mechanism, {-110} vertical facets can appear on a (111)B-oriented surface under specific growth conditions. Fukui et al demonstrated the formation of rectangular-shaped GaAs wire surrounded by the {-110} vertical facets on a GaAs(111)B substrate [21].…”

Time-resolved photoluminescence study on AlxGa1−xAs spontaneous vertical quantum well structures

“…[1][2][3][4][5][6] Metalorganic vapor phase epitaxy ͑MOVPE͒ of ternary alloy layers on V-groove patterned substrates is known to lead nonuniformity of alloy composition driven by the preferential diffusion of one of the constituent materials to the bottom of the V-groove and/or the orientation-dependent difference of incorporation rate among the constituent materials. This nonuniformity is particularly pronounced in the case of Al x Ga 1Ϫx As/V-grooved GaAs since Ga adatoms are much more mobile than Al toward the bottom of the V-groove.…”