Recruitment for year 2005 Research Projects

1
Transparent Conducting Oxides and Oxide p-n
junctions for novel electronics
Transparent conducting oxides (TCO) thin films
are widely used in applications such as the
transparent electrodes of flat panel displays,
solar cells and touch panels. A combination of
the p and n types TCO to form a p-n junction can
result in qualities ideal for optoelectronics.
Some transparent oxides such as ZnO are also
known to be candidates for diluted magnetic
semiconductors, and have potential for
applications in spintronic devices. A number of
materials such as tin-doped indium oxide (ITO),
ZnO, and SnO2 are used in many optoelectronic
devices. ITO is currently the most widely used
TCO. However, as indium is a relatively scarce
element, the cost for ITO production is high. The
other drawback of ITO films is the lack of
chemical stability. The indium of an ITO layer
can diffuse into the organic materials, leading
to the degradation of light emitting diode (LED).
In addition the toxic nature of indium could be
hazardous to human beings and the environment.
At present almost all TCO thin films are n-type
semiconductors as it is extremely difficult to
fabricate a p-type TCO semiconductor. However, it
is crucial to fabricate the p-type in order to
make active circuit components such as diodes in
transparent circuits. This project has three aims

• The fabrication of p type TCO thin films, such as
  CuAlO2 and ZnO by pulsed laser ablation and
  magnetron sputtering, and study on the physics of
  the electronic structure and the optoelectronic
  properties of the transparent p-type conducting
  doped CAO and ZnO thin films.
• The fabrication of TCO p-n junctions, composing
  of p and n type ZnO thin films on glass, quartz,
  ZnO or a-Al2O3 substrates.
• The fabricate of p-n heterostructure junctions
  composing of p-type colossal magneto resistance
  (CMR) thin film with n-type ZnO thin film. This
  type of junction could be modulated by external
  electric and magnetic field.

Recruitment for year 2005 Research Projects