Effect of chemical etching on the photoluminescence of As-Ge-Se chalcogenide glassy semiconductors

Journal of NonCrystalline Solids 90 (I 987) 473 .476 North-Holland. Amskrdam

EFFECT GLASSY

V.V.

OF CHEMICAL ETCHING SEMICONDUCTORS

ON THE PHOTOLUMINESCENCE

OF As-Ge-Se

CHALCOGENIOE

MILOV

Institute Makhachkala, T.N.

of

Physics, USSR

Dagestan

Branch

of

the

USSR

Academy

of

Sciences,

the

USSR,

MAMONTOVA

Ioffe Physico-Technical Leningrad, USSR

1.

473

Institute,

Academy

of

Sciences

of

INTRODUCTION Recently,

considerable

physical

attention

properties

class

of

have

of

glasses

noncrystalline

has jn

the

been

semiconducting

significant

application

focussed

As-Ge-Se materials.

potential

for

on

system The

use

in

studying

the

various

belonging

to

the

materials

of

this

optical

large system

instrumentation

and

microelectronics'. Therefore play

investigation

a substantial

which

are

associated

bination

of

The with

and

the

acid The

in

question

the

of

stationary

the

reflection

0022s3093/87/$03.50 (North-Holland

and

samples etching

was

on

the

these

materials

electron

may

spectrum

participation

in

chalcogenide

glassy

the

%l

mm thick performed

for

0 Elsevier Publishing

recom-

out

of

a He-Ne

laser

the

recombination

the

etching CGSs

in

the

elsewhere5. an

30 min.

with

the

on

started 3,4 .

chemical

PL of

described

The

B.V

of

the

ref.3.

Science Publishers Division)

light

been

compositions

is cut

have

effect on

glasses

with

may shed

CGSs

binary the

(KDH)

of

was

excited

of

alcali

analogy

emission,

of

mode.

Physics

PL which

on

a study

preparation

in

state

primarily

with

(HN03)

compositions,

materials

in

in

of

the

whose

phenomenon

recombination out

deals

Chemical

and

onset

in

defects

this

surface

carried

measurements

subsequently. agents

radiative

report

system. in

of

the

recently

concentrated

used

(PL)

features

structural for

effect in

present

As-Ge-Se

the

the

accounts

the

surface

fairly

photoluminescence

AND METHODS

Studies of

the revealing

(CGS).

MATERIAL

role

In

with

processes

semiconductors

2.

of

role'

for

ingot

and

all

luminescence (h =6328 radiation

the of

ii) being

at

We polished etching the 77

K after

measured

3.

RESULTS

in

the

The measurements

the

binary does

not

compared

sample.

the

the

type

of

(Figs.

the

etching

the

both

with

seen

to

the

effect

the

case

sample

acid

and

enhance

(A)

As33 3Ge3$ jSe3j

The

changes

resulting shown

3 and (B) etching (2) in KOH

in

that

energies.

Note

also

compositions

indication

that

and

thus

or

initiates

affect well observed

the

the

their

change

formation

of

displayed

shape

new

in of

in

the

SUs of

centers This

case and

increase with

etching It

are

has

turned

KOH produces

in

a narrowing

its

shift

of

toward

the

PL spectrum

for

each

We consider

this

as

of

chemical

structural

may apparently

defects

in account

the of an bonds

units

coordination2.

out each

lower

KOH.

with

HN03

employed.

PL spectra

2-3. in

existing

different

2-3.

the

a rearrangement

associated

assumption Figs.

of

KOH is

chemical

etching

in

results amounts

emission

concentration.

PL changes

the

etching

etching relative

the

in

following

chemical

changes

accordingly as

the

studied

to

if

Figs.

particular

seen etching

in

in For

after

from

spectrum the

pronounced

As30Ge30Se40, is

decrease

is

etching.

PL intensity

to

alkali

PL intensity,

more

alkali

substantially

for Etching

with

the

being of

and

in of

agents.

composition,

the

changes

characteristics

etching

another

As3OGe3OSe 0 or dl ferent agents: (19 control sample; etching in HN03; (3) etching

(acid

composition

1 displays

luminescence

different

of

the

depending

agent

sample

a As33.3Ge33.3Se33.3

PL spectra

and of

l-3).

Figure

FIGURE 1 glassy semiconductors:

emission

intensity

changes

and

in

control

spectrum

certain

alkali)

as

new

the

extent)

PL undergo on

produce

However,

that

just studied,

with

a lesser

vs.

shown

glasses,

compositions

etching bands

(to

have

As-Ge-Se

(XI)

This

may

an

SU as

for

the

PL

47s

0.7

0.9

1.1 PWOTON

FIGURE 2 Photoluminescence spectra of CGSs in the As-Ge-Se system after chemical etching in concentrated HN03

LJ

ENERGY

IEVI

FIGURE 3 Photoluminescence spectra of CGSs in the As-Ge-Se system after chemical etching in concentrated KOH

a7

1.1

0.e P”OTON

Indeed, spectrum of

for

tion

of

AsSe3,2

(by by

the

defects

Etching

samples in while

a behaviour

the

of

CGSs

the

originate

for

in

at the

halfwidth accounted

KOH, the

apparently

band

%0.9

typical

shift

dramatic

from thus

the

lEVl

the

the

a preferential

increasing of

of decrease

the

defects

concentraof

the

eV.

As-Ge-Se the

of

in and

bonds,

the

PL intensity,

may be

energies

structural

peaking

enhanced

etched

lower

2)

As-Se

responsible units

a rule,

composition

eV toward

Q a factor

KOH of

structural

unchanged, Such

As3GGe30Se40 by aO.l

PL intensity

destruction

as

the

maximum

u

ENERGV

ternary

system

position

the

spectrum

for

both

of

band

may exhibit by the

polishing

with

HN03

results,

maximum

remaining

slight

variations.

action

of

HN03

PL

which

improves

SUs being

4.

the

stable

optical with

properties

respect

of

to

the

the

surface,

etching

agent.

emission

centers

and

by

the

corresponding

surface

and

CONCLUSIONS The

bulk

data

are

of

ternary

imply nature.

alloy

Chemical

same whose

be surface

used and

that

of to the

the

They

relative

etching

apparently their

obtained the

are

associated

amounts

the

surface

defects

may be affected of

advantage

in of

at with

the

the

various by chemical

CGS material

applications

to

structural

defects

in

the

the the

etching.

question

control

in in

can structure

of

units.

REFERENCES 1)

A.M. Andriesh, All-Union Conf. p. 229.

2)

V.V. Milov, Semiconductors'84,

T.N.

O.V. Luksha, A.V. Ternary Semicond. Mamontova, Gabrovo,

Mironos, & Their

V.V. Ponomar, Applications,

A.V. Chernyshev, Bulgaria, Vol.

3)

V.V. Milov, B.T. Kolomiets, Conf. Amorphous Semiconductors'78, (1978) 448.

T.N.

Mamontova, Pardubice,

4)

V.V. 93.

Milov,

L.V.

Pivovarova,

5)

G.Z. 1444.

Vinogradova,

T.N.

Mamontova,

S.A.

Dembovskii,

N.P.

2.

Proc. (1984)

A.S. Smirnova, Kishinev (1983)

Int.

Conf.

L.V. Pivovarova, Czechoslovakia,

Fiz.

Luzhnaya,

Amorphous

135.

and

Khim.

Zh.

Neorg.

Proc. Vol.

Stekla

Khim.

Int. 2.

11 (1985)

13 (1968)