Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Effect of silicon resistivity on its porosification using metal induced
  chemical etching   A comparison of porous structures formed from silicon (Si) wafers with
different resistivities has been reported here based on the morphological
studies carried out using scanning electron microscope (SEM). The porous Si
samples have been prepared using metal induced etching (MIE) technique from two
different Si wafers having two different resistivities. It is observed that
porous Si containing well aligned Si nanowires are formed from high resistivity
(1-20 $\Omega$cm) Si wafer whereas interconnected pores or cheese like
structures are formed from low resistivity (0.02 $\Omega$cm ) Si wafers after
MIE. An explanation for the different porosification processes has also been
proposed based on the initial doping level where number of dopants seems to be
playing an important role on the etching process. Visible photoluminescence
have been observed from all the porous samples possibly due to quantum
confinement effect.

37
The categories of this paper are: supr-con
25
The categories of this paper are: patt-sol
5
The categories of this paper are: gr-qc
36
The categories of this paper are: cmp-lg
1
The categories of this paper are: cs
10
The categories of this paper are: q-bio
17
The categories of this paper are: q-fin
0
The categories of this paper are: hep-ph
18
The categories of this paper are: econ
21
The categories of this paper are: adap-org
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
14
The categories of this paper are: math-ph
12
The categories of this paper are: nucl-th
22
The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci