Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Direct measurements of band gap grading in polycrystalline CIGS solar
  cells   We present direct measurements of depth-resolved band gap variations of
CuIn(1-x)Ga(x)Se2 thin-film solar cell absorbers. A new measurement technique
combining parallel measurements of local thin-film interference and spectral
photoluminescence was developed for this purpose. We find sample-dependent
correlation parameters between measured band gap depth and composition
profiles, and emphasize the importance of direct measurements. These results
bring a quantitative insight into the electronic properties of the solar cells
and open a new way to analyze parameters that determine the efficiency of solar
cells.

11
The categories of this paper are: hep-lat
31
The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org
18
The categories of this paper are: econ
26
The categories of this paper are: bayes-an
20
The categories of this paper are: acc-phys
22
The categories of this paper are: chao-dyn
30
The categories of this paper are: q-alg
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
28
The categories of this paper are: alg-geom
25
The categories of this paper are: patt-sol
6
The categories of this paper are: astro-ph
33
The categories of this paper are: plasm-ph
34
The categories of this paper are: chem-ph
10
The categories of this paper are: q-bio