Download - Silicon Quantum Dots

7/31/2019 Silicon Quantum Dots

1/21

Silicon Quantum Dots: Grownby Ion Implantation and

annealing

By

Mary Coan


2/21

Outline

History of Silicon quantum dots How they were made

Properties of Silicon Quantum Dots grown

by ion implantation and annealing Advantages/Disadvantages

Different methods to grow Silicon

Quantum Dots Which method is the best?

Summary


3/21

History of Si QDs

1960s: First quantum size effects were

seen in semiconductor nanocrystals

1970s: Louis Brus was working in Bell

Labs researching colloidal synthesizes

1980s: First semiconductor quantum dots

were grown

1990: First visible-photoluminescence

seen from Si QDs


4/21

History of Si QDs

1993: Silicon optoelectronic integratedcircuit is suggested

1993 to present: Si Quantum dots have

been extensively researched Different fabrication methods

microwave plasma decomposition of SiH4

laser breakdown of SiH4

plasma-enhanced chemical vapor deposition

high frequency discharge

high dose ion implantation


5/21

Formation of Si QDs: Ion

implantation and annealing

T.S. Iwayama, T. Hama, D.E. Hole, I.W. Boyd, Vacuum 81, 179 (2006).


6/21

Properties of Si QDs

Photoluminescence

Peak energy and intensity

Size ranges from 1 nm to over 10 nm indiameter

Size distribution within host material


7/21

Photoluminescence

C.W. White, J.D. Budai, S.P. Withrow, J.G. Zhu and S.J. Pennycock, IEEEConference Proceeding 824 (1996).


8/21

Photoluminescence



9/21

Photoluminescence

T.S. Iwayama, T. Hama, D.E. Hole, I.W.Boyd, Vacuum 81, 179 (2006).


10/21

Suggested Mechanisms

T.S. Iwayama, T. Hama, D.E. Hole, I.W. Boyd, Solid-State Electronics 45, 1487 (2001).


11/21

Suggested Mechanisms

R. Krishnan, UR, (2005).


12/21

Range of Sizes

Longer anneals = Larger Si QDs

Ostwald Ripening



13/21

Size distribution within Host Material

M.L. Brongersma, A. Polman, K.S. Min, H.A.Atwater, J. Appl. Phys. 86, 759 (1999).


14/21

Defects within Host

C. J. Nicklaw, M. P. Pagey, S. T. Pantelides, D. M. Fleetwood, R. D. Schrimpf, K. F.

Galloway, J. E. Wittig, B. M. Howard, E. Taw, W. H. McNeil, J. F. Conley, Jr., IEEE Trans.Nucl. Science 47, 2269 (2000).


15/21

Defects within Host




16/21

Defects within Host




17/21

Advantages/Disadvantages

Advantages:

Ease of integration into silicon based

microelectronics (Dots and Process)

Ability to control the PL intensity and peak

energy

Disadvantages:

Large size distribution within host material

Defects within host material

Surface damage (QDs)


18/21

Other Fabrication Techniques

Microwave Plasma Decomposition of

Silane Gas

Laser breakdown of Silane Gas

Plasma Enhanced Chemical Vapor

Deposition

High Frequency Spark Discharge Colloidal


19/21

Which Method is Best?

It depends on what you want to use the

Silicon QDs for.

If you want to make an optoelectical

integrated circuit:

Plasma Enhanced CVD

Ion Implantation

If you want some cool flourishing Si QDs:

Colloidal


20/21

Summary

Properties of Si QDs were discussed

PL dependent on: Anneal time, temperature and process

Ion dose Defects caused by Ion Implantation

Quantum dot surface\host material Causing lower luminescence intensity

A Large size distribution throughout the Host

In the past this was a good technique nowit is outdated by PCVD


21/21

Questions ??