Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Direct evidence of photo-ionization causing luminescence "off" state in
  CdTe Quantum dots   We present a direct experimental evidence of photo-ionized CdTe quantum dot
core having luminescence "off" state at band-edge photo-excitation. We use the
autocorrelation of fluorescence fluctuations from dilute colloidal solution of
CdTe quantum dots in a diffraction limited detection volume to determine their
photo-ionization probability. The ionization probability is in the same order
of magnitude (\approx10-6) as the CdSe and CdSe/ZnS core/shell quantum dots.
Further, we measured the ionization/ neutralization rates (\approx104 s-1)
after addition of {\beta}-mercaptanol and found that ionization rate is
enhanced by two orders of magnitude after the addition. However, a comparable
neutralization rate enhances the light emission quantum yield. The ionization/
neutralization at microsecond time scales puts an upper limit on achieving
better quantum yield by thiol addition. The results also indicate that the
dominant ionization mechanism at band-edge excitation is tunneling.

2
The categories of this paper are: math
7
The categories of this paper are: hep-th
0
The categories of this paper are: hep-ph
23
The categories of this paper are: solv-int
20
The categories of this paper are: acc-phys
19
The categories of this paper are: eess
33
The categories of this paper are: plasm-ph
35
The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
22
The categories of this paper are: chao-dyn
24
The categories of this paper are: dg-ga
21
The categories of this paper are: adap-org
18
The categories of this paper are: econ
16
The categories of this paper are: stat
28
The categories of this paper are: alg-geom