Direct band gap wurtzite semiconductor nanowires

• US 9,493,890 B2
• Filed: 02/19/2014
• Issued: 11/15/2016
• Est. Priority Date: 02/19/2013
• Status: Active Grant

• Current Assignee: Technische Universiteit Eindhoven
• Original Assignee: Technische Universiteit Eindhoven
• Inventors: Assali, Simone, Zardo, Ilaria, Haverkort, Jozef Everardus Maria, Bakkers, Erik Petrus Antonius Maria
• Primary Examiner(s): Kunemund, Robert M
• Application Number:
  US14/184,085
• Publication Number:
  US 20140230720A1
• Time in Patent Office: 1,000 Days
• US Class Current: 1/1
• CPC Class Codes: C30B 11/12 Vaporous components, e.g. vapour-liquid-solid-growth
• CPC Class Codes: C30B 23/007 Growth of whiskers or needles
• CPC Class Codes: C30B 25/005 Growth of whiskers or needles
• CPC Class Codes: C30B 29/40 AIIIBV compounds wherein A is B, Al, Ga, In or Tl and B is N, P, As, Sb or Bi
• CPC Class Codes: C30B 29/44 Gallium phosphide
• CPC Class Codes: C30B 29/605 Products containing multiple oriented crystallites, e.g. columnar crystallites

Abstract

Growth of GaP and III-V GaP alloys in the wurtzite crystal structure by vapor phase epitaxy (VPE) is provided. Such material has a direct band gap and is therefore much more useful for optoelectronic devices than conventional GaP and GaP alloys having the zincblende crystal structure and having an indirect band gap.

Claims

1. A method for wurtzite semiconductor growth, the method comprising:

providing vapor phase epitaxy (VPE) precursors for a first composition including a Gallium (Ga) precursor as a group III species and a Phosphorus (P) precursor as a group V species;

performing VPE of the first composition having a hexagonal crystal structure with a direct band gap.

2. The method of claim 1, wherein the VPE comprises growth of nanowires of the first composition using the VPE precursors.

3. The method of claim 2, wherein the growth of nanowires comprises performing vapor-liquid-solid (VLS) growth of nanowires of the first composition.

4. The method of claim 3, wherein the VLS growth is performed using metal nanoparticles as a liquid growth catalyst.

5. The method of claim 3, wherein the VLS growth is performed in the presence of a hydrogen chloride gas flow to suppress radial overgrowth of the nanowires.

6. The method of claim 3, wherein the VLS growth is substantially performed at a thermocouple temperature between about 600°

C. and 900°

C.

7. The method of claim 6, wherein the VLS growth is substantially performed at a thermocouple temperature between about 700°

C. and 780°

C.

8. The method of claim 3, wherein the VLS growth comprises performing an initial nucleation step at a thermocouple temperature between about 460°

C. and 520°

C.

9. The method of claim 3, wherein the VLS growth is substantially performed at a substrate temperature between about 515°

C. and 776°

C.

10. The method of claim 9, wherein the VLS growth is substantially performed at a substrate temperature between about 603°

C. and 671°

C.

11. The method of claim 3, wherein the VLS growth comprises performing an initial nucleation step at a substrate temperature between about 395°

C. and 446°

C.

12. The method of claim 1, wherein the first composition is a composition selected from the group consisting of:

GaP, GaAs_yP_1-y, In_xGa_1-xP, GaP_yN_1-y, Al_xGa_1-xP, In_xGa_1-xP_yN_1-y, Al_xGa_1-xP_yN_1-y, GaP_1-xAs_yN_1-x-y, and alloys or mixtures thereof.

13. The method of claim 3, further comprising growing a second composition on the nanowires by a VS (vapor-solid) growth method to provide a nanowire structure having a core of the first composition and a shell of the second composition, wherein the second composition has the same crystal structure as the first composition.

14. The method of claim 1, wherein a substrate for the VLS growth is a substrate selected from the group consisting of:

silicon substrates and III-V semiconductor substrates.

15. The method of claim 14, wherein the substrate has a (111), (110) or (100) orientation.

16. The method of claim 1, wherein the first composition includes doping impurities.

17. A method of making an optoelectronic device, the method comprising fabricating an optoelectronic device including a wurtzite direct gap III-V active region;

wherein the wurtzite III-V active region includes a III-V composition including Gallium (Ga) as a group III species and Phosphorus (P) as a group V species; and

wherein the III-V composition is fabricated according to the method of claim 1.

18. The method of claim 17, wherein the optoelectronic device is selected from the group consisting of:

light emitting diodes, semiconductor lasers, single photon emitters, solar cells, single junction solar cells, multi-junction solar cells, photoelectrochemical cells, and solar-driven photoelectrocatalytic devices.