Transcript Document

Clean GaAs(001)-(2x4) Surface
Clean STM Image
Clean Ball & Stick Diagram
16Å
16Å
33rd IEEE Semiconductor Interface Specialists Conference, San Diego, December 5-7, 2002
Page 1
Low Coverage Ga2O Adsorbed
on the GaAs(001)-(2x4) Surface
[110]
[110]
8Å
As
Ga
O
33rd IEEE Semiconductor Interface Specialists Conference, San Diego, December 5-7, 2002
Page 2
Monolayer Coverage of Ga2O
on the GaAs(001)-(2x4) Surface
0
STM Simulations of Clean GaAs(001)-(2x4)
and Monolayer Coverage of Ga2O
8Å
400Å
[110]
[110]
a
As atoms
Ga atoms
O atoms
400Å b
d
c
55Å
0
8Å
33rd IEEE Semiconductor Interface Specialists Conference, San Diego, December 5-7, 2002
Page 3
dI/dV/(I/V) (a.u.)
Approximation of the Density of States for Ga2O
on Both n- and p-type GaAs(001)-(2x4)
-0.91
9
-0.14 -0.14
-0.14 -0.14
n-type Ga2O/GaAs
8
0.39
0.39
0.28
0.28
-0.13
-0.330.39
-0.13
0.39
-0.40
-0.40
-0.54
-0.13
-0.13
-0.33
7
6
Fermi Level
5
4
CB
VB
3
2
-2.0
9
-1.5
-1.0
-0.5
0.0
0.5
Page 4
Mulliken Charges for Ga20As20H32 with Ga2O
10
-2.5
dI/dV/(I/V) (a.u.)
33rd IEEE Semiconductor Interface Specialists Conference, San Diego, December 5-7, 2002
-0.24
-0.24
-0.14 →-0.24
-0.24
-0.24
0.39
0.39
0.28
0.28
0.39
0.39 -0.35
-0.14
-0.14
-0.58
-0.38
-0.38
-0.35
-0.14
-0.14
0.68
1.0
p-type Ga2O/GaAs
7
5
Fermi Level
3
1
CB
VB
-1
-1.2 -0.9 -0.6 -0.3 0.0
0.3
0.6
0.9
1.2
1.5
1.8
Ga2O insertion restores surface As atoms to bulk-like charge
Sample Bias (eV)
33rd IEEE Semiconductor Interface Specialists Conference, San Diego, December 5-7, 2002
Page 5
33rd IEEE Semiconductor Interface Specialists Conference, San Diego, December 5-7, 2002
Page 6