1st year ppt-1.ppt...a"marie"skłodowska/curie"ini4al"...

A"Marie"Skłodowska/Curie"Ini4al"

Training"Network"Postgraduate+Research+on+Dilute+Metamorphic+Nanostructures+and+Metamaterials+in+Semiconductor+Photonics++

Laser&wri)ng&on&nanoscale/LEDs&

based&on&dilute&nitrides.&

Mayank&Sharma&

PhD&Student&

“La&Sapienza”&University&of&Rome.&

&

Supervisors:&Prof.Antonio&Polimeni&&&Dr.Marco&Felici&



Background+of+project+•  Pho ton i c s& i s& impo r t an t& f o r&

informa)on& and& communica)on&

technologies& (ICT).& Eg.,& fiber& op)cs,&

internet.&

•  In&ICT,&photon&sources&are&needed&to&

be&operated&at&1.31μm&and&1.55μm.&

•  U l =m a t e+ g o a l + i s + p r o d u c e+reproducible+ nano?structuring+techniques,+ and+ fabrica=on+ of+nanoscale+LEDs+using+them.&

•  Fabrica)on& of& nanoscale/LEDs& based&

on& laser/annealing& of& hydrogen&

irradiated&(InGa)(AsN)&will&allow&us&to&

move&forward&in&this&field.&



Objec=ves+•  Op)mize&condi)ons&for&complete&N?passiva=on&in&the&InGaAsN&Quantum&Well&

(QW)&using&hydrogena)on&technique.&

•  To&create&site/controlled&nanoscale&light&emi[ng&spots&or&ordered&LED+arrays+by+laser+wri=ng&using&InGaAsN&structures.&

&

•  Materials&development&will&be&targeted&to&key&wavelengths&in&ICT,&i.e.&1.31+μm+and+1.55+μm.+



Single+Photon+Sources+•  Bo]om&row&corresponds&to&semiconductor&based&sources&that&can&be&integrated&

in&optoelectronic&devices.+



QD apps

No&need&of&

posi)on&control&

of&single&QDs!&

Photovoltaics&

Illumina)on&

Biomedical&



Precise&control&of&QD&&

posi)on&and&spectral&emission&

is&needed&for&advanced&applica)ons!&



QD&Diffrac)on&limit&&

>>&typical&dot&dimension&

Solu)on:&Exploit&Near&field!&

Laser+annealing+

Laser&annealing&

using&objec)ve&

Laser&annealing&

using&SNOM&



GaAs

GaAs

GaAsN QW

Laser&wri)ng& can& be& used& to& dissociate& the&N/H& complex& thus& red/shiding&

the&QW&emission&towards&the&peak&energy&(~1.3&eV)&of&the&QW&PL&band&in&

the&as/grown&sample&(i.e.&without&H).&

-10

0

10

20

30

40

50

60

70

80

90

100

110

120

130

0

200

400

600

800

1 000

1 200

1 400

1 600

1 800

2 000

2 200

2 400

2 600

Intensity (

counts)

5 µm

-10

0

10

20

30

40

50

60

70

80

90

100

110

120

0

100

200

300

400

500

600

700

800

900

1 000

Intensit

y (coun

ts)

4 µm

2 µm

before & after laser exposure

Band&gap&modula)on&by&laser&wri)ng&

Focused Laser beam

GaAsN hydrogenated GaAsN

1.3 1.4 1.5

GaAs

QW

Before Hydrogenation

After Hydrogenation

T = 300 K

PL

Inte

nsity

(a.

u)

Energy (eV)

GaAs



Summarizing+&

&

Inser)ng&hydrogen&(by&ion/beam)&increases&the&gap&&

(towards&the&GaAs&value)&

&

&

Removing&hydrogen&(by&light)&decreases&the&gap&

(towards&the&GaAsN&value)&



Results+of+laser+annealing+•  Quantum&confinement&has&been&achieved&by&this&technique.&We&can&make&

quantum&dots&on&specific&loca)ons.&+

PL Imaging



Experimental&techniques&used&so&far&



Experimental+techniques+•  Hydrogena)on&to&

achieve&full&N&

passiva)on.&

•  Macro&&&micro&

photo/luminescence&

measurements&

•  Data&plo[ng&&&

Analysis&

QWs+



Results&&&Analysis&



//&Untreated&–&Black&

//&Hydrogenated&(2B=2*1017&ions/cm2)&//&Red&&

x+1.75+

Annealed InGaAsN/GaAs QW

Non-annealed InGaAsN/GaAs QW

Effect+of+thermal+annealing+

//&Untreated&–&Black&

//&Hydrogenated&(1C=1*1018&ions/cm2)&–&Red&

//&Hydrogenated&(2C=2*1018&ions/cm2)&–&Blue&

x+2.14+ x+3.22+

0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 -5000 0

5000 10000 15000 20000 25000 30000 35000

Inte

nsity

Energy (eV) 1.02 1.04 1.06 1.08 1.10 1.12 1.14

0 5000

10000 15000 20000 25000 30000 35000

Inte

nsity

Energy (eV)

•  Hydrogena=on+usually+causes+a+blue?shiV+in+energy.+•  But,&in&annealed&samples&(700+C+for+10+seconds),+the&effect&was&not&observed.&

Inte

nsity

(arb

.uni

ts)

Inte

nsity

(arb

.uni

ts)



Hydrogena=on+of+different+set+of+samples+



InAsN+vs.+GaAsN:+H+role+•  Hydrogen&has&more&effect&on&GaAsN&w.r.t.&InAsN.&

InAsN/GaAs QW

1.00 1.20 1.40

PL In

tens

ity (a

rb. u

nits

)

Energy (eV)

GaAs1-x

Nx/GaAs QW

x=2.9% t = 6 nm

untreated

dH=5×1017 cm-2

dH=2.5×1019 cm-2

dH=5×1019 cm-2

GaAs

T = 10 K

P = 5 W⋅cm-2

GaAsN/GaAs QW



What+happens+for+Intermediate+cases?+



Laser+annealing+of+GaAsN+using+SNOM+

(a):%This%QD%is%fabricated%with%laser%power%of%1.1%mW%for%1%sec%

(b):%Measurements%from%QDs%fabricated%at%different%powers%with%exposure%@me%of%1%sec%

(b)



Summary+•  Blue/shid&in&thermally/annealed&sample&is&difficult&to&achieve&because&of&

forma)on&of&In/N&bonds.&

•  In/N&bonds&causes&inhibi)on&of&hydrogen&effects.&

•  The&reason&might&be&the&strain,&cohesive&energy,&etc.&which&inhibits&hydrogen&to&

passivate&nitrogen&in&indium&rich&samples.&

•  Non?annealed+samples+have+shown+significant+blue?shiV+which&is&an&important&

step&in&my&project.&

•  These&new&samples&are&also&emi[ng&at&room&temperatures&that&shows&that&they&

are&good&for&prac)cal&applica)ons.&



Outputs–publica=ons,+talks,+posters,+outreach+•  Talks:&

1.  “Hydrogena4on" of" InGaAsN"QW"Samples”/&University& of& Cadiz:& 18th&May&

2016.&

2.  “Effect" of" In/N" bonds" on" nitrogen" passiva4on" in" dilute" nitrile"semiconductors”/&University&of&Montpellier:&1st&September&2016&(France).&

3.  “Laser" wri4ng" of" nanoscale" LEDs" based" on" dilute" nitrides”/+ Mid/term&

review&mee)ng&of&PROMIS&network,&London&(UK):&7th&December&2016.&

•  Poster:&

1.  “Indium" influence" on" the" hydrogen/induced" passiva4on" of" nitrogen" in"dilute" nitride" semiconductors”:% 19th& Interna)onal& Conference& on&Molecular& Beam& Epitaxy& (MBE& 2016):& 4/9& September& 2016,&

Montpellier&(France)&

&

& & & & & & & & & & & & & & & &&

&



1st year 2nd year 3rd year

•  Design&of&samples.&

•  Adequate&

hydrogena)on&

values.&

•  Fabrica)on&of&site/,&size/,&and&

shape/controlled&

nanoscale&LEDs&

emi[ng&at&the&

desired&wavelengths.&

•  Integra)on&of&nanostructures&&in&

the&

telecommunica)on&

industries&for&

prac)cal&implementa)ons.&

Strategic+plan+for+my+PhD+



Acknowledgement+&+Collabora=ons+



Appendix&

1st year ppt-1.ppt...a"marie"skłodowska/curie"ini4al"...

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