DAI HOC
QUdc GIA
HA
NOI
TRUdNG
DAI HOC KHOA HOC
TU NHI^N
•
•
• •
•
«
•
CHE TAO VA KHAO SAT
TINH
CHAT CUA LOP
CHUY^N
TI^P
p-n
TREN CO
SO MANG
M6NG ZnO VA KHA
NANG
UNG
DUNG
CUA CHUNG
Ma
so:
QT -
08
- 16

Trong cac hop chat ban dan, ZnO la chat ban dan c6 do rong
vomg
cam
Ion
(-'3,3eV
a nhiet do
phong),
do ben vung va nhiet do nong chay cac,
gia
thanh
re. ZnO
thiromg
dugc
dung lam vat lieu cho cac
Hnh
kien quang
dien
tir.
ZnO c6 hieu suat
lucmg
tu phat quang c6 the dat tai gan
100%,
ma
ra trien vong trong viec che tao laser ZnO nhiet do
phong.
Mang mong ZnO
CO
do dan dien va do truyen qua quang hoc cao trong mien anh sang nhin thay
dugc
umg

true
nano
vai nhieu hy vgng trong viec che tao mot the he
linh
kien
mai
c6 nhieu tinh
chat
UTJ
viet so vai cac mau khoi.
2.
Noi dung nghien
ciifu:
De
thuc
hien
dirge
muc tieu neu
d
tren,
d^
tai da giai quyet dugc eac
vSih
de sau:
+
Che tao mang ZnO c6 chat
liigng
cao bang
phuofng
phap phun xa r.f.

catdt
Univex-450
va boc bay nhiet trong chan khong
Univex-300
vao boat
d6ng
c6 hieu qua.
+
Che tao thanh cong cac
loai
bia ZnO va ZnO pha tap bang phuofng
phap gom
truy6n
thong.
-h Tim
dugc che do cong nghe de che tao mang ZnO va mang ZnO pha
tap In tren de p-Si va de thuy tinh bang
phucDmg
phap phun xa r.f. magnetron
tren thiet bi Univex-450.
+
Che tao mang quang tra ZnO nhay a vung UV.
+ Che tao thanh cong pin mat trai n-ZnO:
In-p-Si
de lam cam bien nhay
quang.
I
If
f
+ iJng

luan
tot nghiep
1/
Nguyen Si
Hieu,
''Che
tao va khao sat mang ZnO
d6'
thuy tinh
bang hoc bay nhiet kem axetat trong chan khong" Ha Ngi - 6/200L
2/
Nguyen
Hong Viet,
"Che
tao va khao sat mang ZnO pha tap
Al
tren de thuy tinh bang phuong phap
phiin
xa R. F
magnetron",
Ha
Ngi-
6/2002.
* Da
hudng
dan
1
luan van cao hoc:
r
1/

Chi
phi
nghiep vu chuyen mon : 10.300.000 d
Chi
phi
khac (QLCS): 600.000 d
Da
thSng
qua churng
tijr
tai phong tai
vii.
Xac
nhan ciia
ban
chii
nhiem Khoa
(Ky va ghi ro ho ten)
Chii tri di
tM
(Ky va ghi ro ho ttn)
PGS.TS.Nguyen
The Binh PGS.TS.Ta
Dinh Onh
Xac nhan
ciia Trucmg
DHKHTN
»M6
HI?U
TRl/ONG

n-ZnO:In
under
reverse bias conditions. These
resuhs
indicated that
ZnO:In
films
prepared by the r.f. magnetron sputtering are good enough to be used
in photoelectrical devices.
5.
The content of research.
The p-type Si (100) wafers (7-25
Qcm)
were used as substrates for the
ZnO:In/Si
heterojunction. Si (100) wafers were cut into pieces of
lilcm.
Prior to the deposition, the wafers were dipped into buffered oxide etchant
(HF:H20
= 1:7) for
1
minute to remove native oxide. Then the samples were
ultrasonically cleaned with boiling acetone, ethanol, and de-ionized water for
10 min. ZnO:In films were deposited with an r.f magnetron sputtering
system using a
ZnOiIn
(2%) target with diameter of 7.5 cm and 0.5 cm thick.
The sputtering parameters were optimized at a substrate temperature of 150
''C,
r.f. power of 250 W and sputtering Ar pressure of

the
eleventh Vietnam-German seminar on Physics
and Egineering, Nha trang 2008 (In the press).
2/
Photoconductive
UV detectors
based
on ZnOfdms
prepared by RF
magnetron sputtering
method.
Nguyen Viet Tuyen, Ta Dinh Canh and
Nguyen Ngoc Long. Comm. In Physics, 2008 (in the press)
7.Conclusion
* Obtaining the aims of the project.
* Training 2 graduate students,
1
master student.
MUC LVC
Trang
MQ
DAU 1
Chuang
1:
TONG
QUAN VE
VAT LY BAN DAN 3
1.1 Co so phan loai vat lieu 3
1.2
Phan loai vat lieu ban dan 5

blend)
13
1.4
Cau tnic
viing
nang
lugng
cua ZnO
14
1.4.1
Cau tnic vung nang lugng cua ZnO dang luc giac 14
1.4.2
Cau
true
vung nang lugng cua ZnO dang gia kem
15
1.4.3
Cau tnic vung nang lugng cua ZnO dang lap phuong dan gian
ki6u
NaCl 16
1.5
Tinh chat dien
ciia
ZnO 17
1.5.1 Dich chuyen trong dien trucmg thap
17
1.5.2 Dich chuyen trong dien trucmg cao 18
1.5.3
Tinh chat dien cua ZnO pha tap 19
1.5.3.1

1.8.1
Tilp
xuc p-n dong
thi
30
1.8.2
Tiep xuc p-n di the
31
1.8.3 Tiep xuc Ohmic 33
Chuang
2:
CAC PHUONG PHAP
THI/C
NGHIEM 36
2.1 Cac ky thuat phun xa 36
2.1.1
Phiin
xa nguon mot chieu
37
2.1.2
Phiin
xa nguon xoay chieu 39
2.1.3
Phiin xa magnetron 40
2.2 Nghien curu cau tnic bang phuang phap
nhilu
xa tia X 41
2.3 Quan sat hinh thai be mat bang kinh
hiln
vi dien tu quet (SEM) 43

Trong cac hgp chat ban
din,
ZnO la
chit
ban
din
c6 dg rgng
viing
cam
Ian
(-3,3eV
d
nhiet do phong), do ben
vvhig
va nhiet do nong chay cao, gia thanh re. ZnO
thuang dugc diing lam vat lieu cho cac linh kien quang dien tu. ZnO c6 hieu suat lugng
^
y
t
'
tu phat quang c6 the dat tai gan 100%, ma ra trien vgng trong viec che tao laser ZnO
nhiet do phong. Mang mong ZnO c6 do dan dien va do truyen qua quang hgc cao trong
mien anh sang nhin thay dugc ung dung lam dien
cue
trong suot cho pin mat trai chat
lugng cao va gia thanh ha. Cac mang ZnO dan dien trong suot con dugc su dung trong
cac man hinh tinh the long, cac cua so dien tu, cac thiet hi quang hgc uon dugc, cac
guang phan xa nhiet de
phii
va kho phu, tham chi bgt ZnO con c6 ung dung trong che

di?n,
can
cur vao
viec cac dien tu khong lap
dly
hay c6
lip dly
cac vung nang lugng.
DI
lam viec do
ngoai viec phai biet cac vung nang lugng ta con can
nhac lai
rang vi cac
di?n
tu tuan
theo thong ke Fermi - Dirac cho nen trong moi trang thai vat
ly
(dac trung bai ham
song va hinh chieu spin)
ciia
dien tu chi c6
thi
hoac la khong c6 hat nao, hoac la c6
mot hat; khong the c6 hai dien tu
ciing t6n
tai
d6ng
thai trong mot trang thai vat ly. Khi
trong mot trang thai vat ly da c6 mgt dien tu roi thi ta noi trang thai do da bi chiem
hoac da day; neu con c6 cac dien tu khac thi cac

Band
Hinh 1.1: Cau
true
viing nang
lu(mg
cua
kirn
loai,
ban dan va chat
each di^n
Gia su
chit rln
c6 mgt vung nang lugng ma mgt
phin dS
dly,
mgt
phin
con
trdng.
C)
nhiet do
T ==
0 cac trang thai vdi nang lugng duai muc Fermi
Ep
da
dly
hit,
con cac
3
trang thai vai

lam thay doi
ph&n
bo nang lugng.
C) nhi^t
do
T #
0 c6 them
di$n tir
vcri
ntog
lugng tren muc Fermi vi
nhung trang thai chua
dly
vai
nSng
lugng
dudi
muc Fermi,
s\r
thay doi him ph&n
b4
khi truyen nang lugng cho
hf
cang de dang han, du cho do la
n&ig
lugng
rit
b6.
Khi ta
dat chat

m^t
phan da day va mot
phSn
con trong ggi la
viing
din.
Kim loai c6
clu
tnic viing
ndng
lugng va su phan bo dien tu trong vimg
din
nhu
da
trinh bay a tren, nen la
chit
din
dien.
Trai lai, neu pho
nSng
lugng
ciia chAt
rin c6 mgt vimg
cim
vai
mpt
be rgng
A£
du
lom,

Chit
tin c6 clu tnic va su phan
b6 di^n
tu nhu
v$y
la chat
each
di^n.
Vimg nang lugng duai viing
elm,
gdm cac trang thai
da
dly,
ggi li
\ung hoa tri. Cac dien tu
lip
dly viing hoa tri
gpi
la dien tu hoa
trj.
Viing
elm
cang
rpng thi tinh chat
each
dien cua
chit
rln cang
t6t.
6

din
cua chat dan
di?n.
Viing nang
lugng con tr6ng do a phia ben ngay sat vimg
elm
cung
duac
gpi
la viing dan. Theo cong thirc phan
b6
Femii,
n6ng
dp
di^n tij
trong viing
din
CO
dp
Ion
vao ca:
n^^
e-'"'
(1-1)
e^^
+ 1
nh6 Hon
nhigu
so
v6i ndng d$

lugng v6
ciing gin ning
lugng cic
tr^g
thai
dly
cho nen
dudi
tic
d\mg
cua mot dien truang khong can
Ion llm
cic
di§n tii
trong vung hoa tri ciing c6
thi
thay
doi
sir
phan bo va do do cung tham gia vao
s\r
xult
hi^n
dong
di^n.
So cic trang thii
trdng nay trong viing hoa tri
bing s6 di^n
tu trong
viing

loai v|t
lifu
bin din
1.2.1
Bin
dan thuan
e
«
e
'
«
i
#
s
#
.
«a
«• «•
'
# S # I
#
e
ee
«•
••
'
#
S
'#
S # e

bin
din
rieng va
cung con gpi la ban dan loai I.
Vai loai vat lieu nay khi
6 nhi^t
dp OK, vimg
din
hoan toan trong, khong c6
di^n
tir
din.
Khi nhiet dp tang len, dien tu a vimg hoi tri c6
thfi
thu dugc mpt
ning
lugng
cIn thiSt
de vugt qua viing cam va nhiy len viing din,
dfi
l^i
a
viing hoa tri
"iP^
™^
khuy^t
dien tu.
K6t
qua la
a

Fermi dugc xac dinh bdi cong thuc:
Vi£^^3
m^
(1.2)
2
4
m,
6
nhiet dp cao han, trir mpt sd truang hgp khi c6
s\r
chenh
l#ch I6n
ve khoi lugng
hieu dung nhu
a
InSb,
su
chuyin
dich cua muc Fermi theo
nhi^t
dp
li
khdng ding
kc.
Do do, ndng dp hat tai rieng cua ban
din thuIn
c6
thi
dugc
bilu diln

\ iing hoa tri. Dp dan trong ban dan thuan dugc xac djnh bdi bieu thuc.
a
=
q(nn^
+ pjip)
(1.4)
Trong do n,
jin
tuang img la ndng dp va dp linh dpng cua
di?n
tir; p,
fip
tuang iimg
la nong dp va dp linh dpng cua
Id
trdng, q
=
e la
di?n
tich nguyen td. Nhu vay
djc dilm
dan dien rat quan trong cua chat ban dan thuan la su tham gia ddng thdi vdi sd lugng
nhu nhau
ciia
ca
di^n
tir tren viing
din lln l6
trdng trong viing hoa trj.
D$c

chi
khi
nang img
dyng thyc
tiln.
Vi vay ngudi
ta
chu dpng pha
th6m m$t
lugng
nguyfin
t6
khac
lo^i
vao chat bin
din
tinh khilt
di
d^t
dugc cic tinh
chit
mong mu6n. Trong
m^t
v^t
li?u
nhu
v$y,
tinh
din di^n
xult

tinh khiet mi ngudi
ta
CO
the tao ra dugc
hoic
bin dan tap chat loai n
hoic
la ban dan tap chat loai p.
1.2.2
Bindlnlo^ip:
e e e
^
#
I •
S
# e
a e a
Hinh
1.3:
Lien ket trong ban dan
iogip
Gia sir
ring
c6 nguyen tir C vdi
n-1
di^n
tu vanh ngoai (hoi tri
n-1)
mi ham song
gidng nhu ham song cua n-1 trong sd n

cd cac dien
tii,
trong viing hoa trj cd them
Id
trdng.
Hi^u
sd ndng dp Id trdng va ndng dp dien
tii
la mpt lugng khdng ddi va
blng
ndng dp tap
chat.Cac
l6
trdng la cac hat tai dien chinh.
Chit
ban
din
nay gpi la chat ban
din
loai p
(positive). Ndng dp
l6
trdng trong ban
din
loai p:
p = (N^N J cxpi-^)
(1.5)
2kgT
1.2.3 Ban dan loai n:
e e e

logi
n
Xet mpt
chit
ban
din
cd chua cac nguyen tu
ciia
mpt chat A nio dd. Gii sd
m8i
nguyen tir
/4
c6 n dien tir vanh ngoai ( hoi tri n ) la nhihig
di?n
td trd thanh m5i nguyin
tir
luu
dpng trong
chit
rln.
Tit
ca cac
difn
tu nay lap dly vung hoi trj khi
T =
0 vi
cung chi vira du de lap day viing hoa trj. Ta hay thay the mpt nguyen tu A trong tinh
th^
bang mpt nguyen tu
5

di?n
tu nay chi cd the chilm
m^t
trang thai trong viing dan va trd thanh dien tir dan. Do dd
nlu
ta pha
t^p
chit B vio
chat ban dan A de cac nguyen tu B thay the mpt sd nguyen tu A, thi trong vung
din s€
CO
cac dien tir dan ngay ca d nhiet dp
r=
0, chat bin
din
trd thanh
din di^n
mi cic
h^t
tai
di^n
chinh la cac
di^n
tir.
6
nhiet dp
F
9^
0 vi cd them cic
di^n

qui trinh
chuyen
ddi
h^t
tii tir viing hoa
tq
len viing
din
li khdng ding
kl.
H^t
tii
di^
dugc
t90
8
thanh chu
ylu
li do
kit
qui cua qui trinh ion hoi cac nguyen tu tap
chit.
Do
v$y,
ndng
do can blng cua
h^t
tii trong trudng hgp nay phu thugc vao ndng dg
t^p
chit

han nen se den
liic
toan bg cac nguyen
tiir
t^p
chat bi idn hoa het. Trong trudng hgp nay, ndng dg hat tai blng ndng dg nguyen
td
t^p
chat va trd nen khdng thay ddi theo nhiet dg,
tire
la:
n = Nd
va
p = Na
Nhiet dp
Ts,
ma tai do xay ra
hi?n
tugng nay,
ph\i
thugc vao muc
ning
lugng
t^p
chat va ndng dp tap chat.
Cy
the la :
Ts =
^''{j,
(1.7)

trong cac ban
din
tap
chit
it bj thay ddi theo nhiet dp nhu trong trudng hgp cac chat ban
din
thuan khiet.
D$c dilm din difn
chu ylu blng
m$t lo^i h9t
tii
19!
ft bj
phy thu^c
vio
nhi^
t
lam cho cic ban
din
t^p
chit trd thinh mpt
vit li^u
qu^^
trong
lihh
v\rc
chi
t^o
ciclin
kien dien tu nhu diode, transistor

cich
di^n
ma viing
elm
cd
bl rOng A
rlt be, d nhiet dp
Ti^O
mpt sd dien tu bi kich thich tir viing hoi trj len vung
din
va
tr
thanh dien tu dan, de lai trong viing hoa tri nhumg
I6
trdng ciing li cic
h^t
tii
di^
Ndng dp cac hat tai phy thugc
nhi^t
dg T theo cdng thuc . Cic chat bin dan dd dug
gpi la cac chat ban
din
thuan, cd tinh chat cich
di^n
khi dugc
giO"
d
nhi^t
dp

han ndng dp
Id
trdng. Tap chat
lo?ii
nay gpi la chat
hifin di^n
tu (donor).
M$t
khic,
n^
ta pha tap de thay mpt sd nguyen tir mpt
loai
nio dd
ciia
chat ban
din
blng
nhthi
nguyen tu c6 cau tao tuang ty nhung vanh ngoai cd bdt di mpt
di^n
tu, thi ta
s€
du^
mpt chat ban dan loai p ma Id trdng lai la
h^t
tai chinh , ndng dp
Id
trdng
Idn hem nil
do dien tir. Tap chat loai nay gpi la tap chat nhan

di^n
tich duan|
nay cac dien
lir
dan c6 cac trang thai lien kiet gidng nhu nguyen tu hydro, vdi
ninj
lugng am so vdi nang lugng tdi thieu cua dien tir ty do trong viing
din.
Mire
nan|
lugng gian doan nay nam trong
voing
cam va gpi la muc
ciia
tap
chit
hiln
di^n tii
(min
donor ). Ngugc lai, so vdi nguyen ni A thi nguyen tu C con
thilu
mpt
di?n
tu, cho
nft
khi
C thay vao cho
ciia
A thi nguyen tir C con
bit

diu
ngugc lai so vdi ning lugng cua
trang
thai
trdng, tinh tir
mure
Fermi
nim
trong vung cam, cho nen neu quy
vi
trang thii
trdng ciia
di^n
tu thi nguyen tu C tao ra them cac muc ning lugng gian doan cd gii tri
duong so vdi cue dai viing hoa tri, nghTa la cung
nlm
trong viing cam. Cac muc niy
gpi la cic muc ciia tap chat nhan dien tu (muc acceptor).
1.3 Cau
true
tinh the ZnO.
Ve mat ly thuyet, ZnO khdng phii la mpt vat
li?u
mdi dugc khim phi. Cic nghiin
cim tren ZnO da dugc thyc
hi?n
lien tyc trong nhieu thap ky, ve
mit
tinh chat cua nd, di
cd cac bai bio tir

lye
giac wurtzite.
Cau tnic luc giac wurtzite la cau tnic dn dinh va ben vimg
ciia
ZnO d dieu
ki^n
nhiet dp phong va ip suat khi quyin va thupc ve nhdm khdng gian
P63mc hoic
CV-
Cd thi hinh dung mang wurtzite gdm hai phan mang lye giac xep chat (hpc)
Idng
vao
nhau va dugc djch di mpt khoang bang u = 3/8 chiiu cao (trudng hgp cau tnic ly
tudng),
mdi phan mang nay gdm 4 nguyin
tii
cung loai trong mpt d mang dan vi. Mpi
nguyen tir nhdm II dugc bao quanh bdi 4 nguyin tu nhdm VI hoac ngugc lai. Trong
thyc ti, hai phan mang nay
Idng
vdi nhau khdng
diing
vdi gia trj 3/8 chiiu cao ma
tiiy
theo timg loai cation, gia tri djch
chuyin
nay se khac nhau. Mpt trong nhung tinh
chit
dac trung cua phan mang luc giac xip chat la gia tri ty sd
giira

liin
kit cdng hoa tri, li loai liin kit pha trpn bao gdm 67% liin kit ion va 33% liin kit
cdng hoa tri. Dac diim quan trpng
ciia
liin kit cpng hoa
trj
li tinh
dj
hudng vi tinh bio
hoa vi mdi nguyin tu chi cd the cd nhiiu nhat mpt sd lien kit
cOng
hda
trj
nio dd.
O
Hinh
1.5
Cau
true
mang tinh the luc giac kieu wurtzite cua ZnO.
1.3.2. Ciu triic
m^ng
lap
phuong don
giin kieu NaCl
Nhom ddi ximg khdng gian cua cau tnic nay la Fm3m. 6
m^g
co sd
ciia
clu true

dm
gidn
kiiu
NaCl ciia
ZnO.
12
COng gidng nhu
m$t
sd
chit
bin
din
A°B^,
ZnO clu
true kiiu
wurtzite cd
thi biln
ddi sang hinh thii clu
true
gii
bin
1|^
phuang don giin
kiiu
NaCl d ip
suit thdy
fihh
dii
cao
vi ngugc

sy
bien ddi cau tnic vdi ip
suit
chuyin pha p =
lOGPa
va hoan thinh d khoing
15GPa.
1.3.3. Cau true mang lap
phvorng
gia kem
Day cung la mpt trang thai cau tnic gia bin cua ZnO nhung xuat hien d nhiet dp cao.
Nhdm ddi xumg khdng gian ciia cau tnic nay la
T^
- F?
3m va gdm hai phan mang lap
phuang tam dien (fee) xuyin vao nhau 1/4 dudng cheo cua d mang. Mdi d co sd (hinh 1.3)
chira bdn phan tu ZnO vdi cac tpa dp
ciia
4 nguyin tu Zn la:
(0,0,0),
(0, 1/2, 1/2),
(1/2,0,
1/2), (1/2, 1/2, 0) va tpa dp ciia 4 nguyin tu O la: (1/4, 1/4, 1/4), (1/4, 3/4, 3/4), (3/4, 1/4,
3/4),
(3/4,3/4,
1/4). Trong cau tnic nay, mpt nguyin td bit ky dugc bao bdi bdn nguyin tu
khac loai. Mdi nguyen tu O dugc bao quanh bdi bdn nguyin tu Zn
nim
d dinh ciia tu
di?n

mong
lap
phuang
gid
kem cua tinh the ZnO.
13
1.4. Cau
triic
viing ning
Ivgng
cua ZnO
1.4.1. Cau
true viing
ning
Ivgng ciia
ZnO dang
lye
giic wurtzite
Tat ca cac hgp chat
A"B^
diu cd vimg cam thing vi dp rgng vimg elm giim khi
nguyen tu lugng ting. Mang tinh thi ZnO dang wurtzite clu
t^o
tir hai
m^ng
lyc
giic
ling
vao nhau, mgt mang chua anion va mang con lai chira cation. Cic
victo tjnh

b^
= 27ic-'(0,0,1)
(1.11)
Cau tnic luc giac ciia ZnO thugc nhdm ddi xung khdng gian
CV
(P63mc).
Vimg
Brillouin thir nhat la mpt khdi bat
di?n
dugc biiu dien trin hinh
1.8.
Hinh
1.8
Vimg Brillouin
ddi vai mgng tinh thi wurtzite.
14
Hinh
1.9 Cdu
true
vung ndng
lir^mg
cm mgng tinh the wurtzite.
Bang phuang phap nhiiu loan cd thi tinh dugc viing nang lugng cua mang lyc
giic tir viing ning lugng ciia mang lap phuang. So dd viing din (CB) va viing hda trj
(VB) ciia hgp chat nhdm
A"B^'
vdi
m^g
tinh the lyc giic dugc cho trin
huih

Hinh
1.10.
Vung
Brillouin cua mgng tinh the
lap
phuang gid kem
15
Mang lap phuang gia kim cd cau tnic ddi
xixng
tjnh tiin cua
m^ng
1^
phudj
tam mat vdi cac vecto tinh tiin co sd li:
a,
=^a(U,0);
a,
=^a(l,0,l);
a,
=^a(0,U)
d.
^ ^
Mang dao dang lap phuang tam khdi cd cic vecto tinh tiin ca sd la:
-I
b,
=2Ka-'(l,l,-l);
b,
=27ia-'(l,-l,l);
bj =2nc-(-1,1,1)
(1.13

phuang gi
kim.
So dd viing nang lugng
ciia
ZnO vdi cau tnic tinh
thi
d^ng
lyc giic
kiiu wurtziti
lap phuang gia kim (zinc blende) va lap phuong don giin
d^g
NaCl dugc cho
ti<
hinh 1.11.
15
to
5
S
I"
?
-5
III
V
-15
-20
• -^ —"^^
•
^^^^>r:^\
B4
ZaO

hi#u di^n
thi dinh
thiing
Idn,
khi ning duy tri trudng dien cao Sy djch chuyin
electron trong vat
lieu
bin
din
cd thi dugc khao sit ddi vdi cic trudng
di^
thap vi cao.
-
Ddi vdi trudng dien du thap, ning lugng cua cac electron thu dugc tir trudng
ngoai la nhd khi so sinh vdi ning lugng
nhi^t
cua chiing, vi vi thi phd ning lugng
ciia cac electron khdng bj thay doi bdi trudng ngoai nhd do. Khi dd tdc dp tin
x^
xac dinh cua cac electron linh dpng phy thupc vao ham phan bd
ciia
cac electron,
dp linh dpng
ciia
electron ddc lap vdi trudng ngoai va dinh
luat
Ohm dugc quan
sat thay.
-
Khi trudng ngoii ting tdi diim ma ning lugng cic electron thu dugc tir trudng

Idp
epitaxy. Ddi vdi vat lieu ban dan, nd tiet
Id
ndng dp hat
tai,
loai hat tai va dp linh dpng
ciia
chiing. Cy thi han, sd
li^u
thyc
nghi^m
cua cic phip
do Hall trong dai nhiet dp
Idn
tir 4,2 - 300K cung dp
nhung
thdng tin dinh lugng vi dg
tinh khiit, cac sai hong mang, tinh ddng diu cua vat lieu, co chi tan xa Hi sd Hall vi
dien trd
suit
p dugc xic dinh bing thyc nghiim va sau dd liin hi vdi cac tham sd dien
qua (ddi vdi tinh dan loai n)
RH
=
rn/ne
va
JIH
=
^H^P
trong do n la ndng dp