A. Hoffmann, Institut für Festkörperphysik, TU Berlin
I
4
- donor bound exciton complex in ZnO
Reflection spectrosc py
Why VCSELs andwhy quantum dots (QDs)?
InGaN insertions inGaN as
dense arrays ofQDs
Surface lasing incavities withoutDBRs:
Narrow line, superlinear growth in intensity,
singlemode character,
high threshold excitationdensity
AlGaN/GaN DBRs and their impacton
the threshold excitationdensity
Room temperature photopumpedVCSELs
Far-field patterns of lasing and spontaneous
emission
Efficient InGaN/GaN/AlGaNLEDs
Resonant-cavity LEDs as prototypes of
current-injectionVCSELs
Conclusions
B.K. Meyer (Begi n der gemeinsamen Nitridforschung )
Undoped ZnO
Id ntificati n of donors in ZnO
3.356 3.358 3.360 3.362 3.364
Energy (eV)
ZnO as grown
PL Intensity (arb. units)
I
4
T = 4 K
(SIMS)
I
6
ZnO:Al
N
Al
10*N x
I
8
ZnO:Ga
n
e
= 2*10
18
cm
-3
(Hall)
(SIMS)
N
In
10
17
cm
-3
I
9
ZnO:In
Diffusion and annealing experiments:
Al, Ga and In doping results in
bound exciton lines I
6
, I
8
, I
9
Annealing above 600
°
C reduces I
4
I
4
: Hydrogen
Hydrogen leaves ZnO lattice
I
6
/ I
0
: Aluminum
I
8
/ I
1
: Gallium
Observation of D
0
X in PL is directly
correlated to specific donors
I
9
/ I
2
: Indium
B. K. Meyer et al., pss(b) 241, 231 (2004)
