Growth of III-V compound semiconductor nanowires on silicon substrates
The present invention relates to growth of III-V semiconductor nanowires ( 2 ) on a Si substrate ( 3 ). Controlled vertical nanowire growth is achieved by a step, to be taken prior of the growing of the nanowire, of providing group III or group V atoms to a (111) surface of the Si substrate to provide a group III or group V 5 surface termination ( 4 ). A nanostructured device comprising a plurality of aligned III-V semiconductor nanowires ( 2 ) grown on, and protruding from, a (111) surface of a Si substrate ( 3 ) in an ordered pattern in compliance with a predetermined device layout is also presented.
1. A method of growing at least one III-V semiconductor nanowire from a Si surface, the method comprising a step of providing a group III material pre-flow at a predetermined elevated temperature to provide a (111)B-like group III material-terminated Si surface prior to growing of the III-V semiconductor nanowire;
wherein the III-V semiconductor nanowire is grown by particle assisted growth and the method comprises the steps of:
providing the group III material pre-flow at the predetermined elevated temperature giving diffusion of group III material into a growth catalyst particle to provide the (111)B-like group III material-terminated Si surface;
introducing group III material and group V material precursors at a high temperature to grow a thin III-V nucleation layer with (111)B orientation;
lowering the temperature; and
growing said at least one III-V semiconductor nanowire from the nucleation layer at the lowered temperature.
2. The method according to claim 1 , wherein a plurality of III-V semiconductor nanowires are grown from a nucleation layer and the method further comprises the step of growing a semiconductor coalescence layer from the plurality of III-V semiconductor nanowires such that the coalescence layer is substantially single domain.
3. The method according to claim 1 , wherein the Si surface is a Si(111) surface.
4. A method of growing at least one III-V semiconductor nanowire from a Si surface, the method comprising a step of providing a group III material pre-flow at a predetermined elevated temperature to provide a (111)B-like group III material-terminated Si surface prior to growing of the III-V semiconductor nanowire;
wherein the method comprises the steps of:
providing a Ga material pre-flow at the predetermined elevated temperature giving diffusion of the Ga into a growth catalyst particle to provide the (111)B-like Ga-terminated Si surface;
introducing Ga material and P material precursors at a high temperature to grow a thin GaP (111)B nucleation layer;
lowering the temperature; and
growing said at least one III-V semiconductor nanowire from the nucleation layer at the lowered temperature.
5. A method of growing at least one III-V semiconductor nanowire from a Si surface, the method comprising a step of providing a group III material pre-flow at a predetermined elevated temperature to provide a (111)B-like group III material-terminated Si surface prior to growing of the III-V semiconductor nanowire;
wherein the method comprises the steps of:
providing an In material pre-flow at the predetermined elevated temperature giving diffusion of the In into a growth catalyst particle to provide the (111)B-like In-terminated Si surface;
introducing Ga material and As material precursors at a high temperature to form a thin GaAs (111)B nucleation layer;
lowering the temperature; and
growing said at least one III-V semiconductor nanowire from the nucleation layer at the lowered temperature.