Work Function Modification of Tungsten-Doped Indium Oxides Deposited by the Co-Sputtering Method

Area of Science:

• Materials Science
• Solid State Physics
• Thin Film Technology

Background:

• Indium oxide (In2O3) is a key transparent conducting oxide (TCO).
• Tungsten doping is explored to enhance TCO properties.
• Work function modification is crucial for device integration.

Purpose of the Study:

• To investigate the work function modification of tungsten-doped indium oxides (IWOs).
• To explore the co-sputtering of In2O3 and indium tungsten oxide for IWO thin film fabrication.
• To correlate tungsten content with the electrical, optical, and work function properties of IWOs.

Main Methods:

• Radio frequency (RF) magnetron co-sputtering of In2O3 and In2O3-WO3 targets.
• Controlled elemental deposition to vary tungsten content in IWO thin films.
• Characterization of work function, carrier concentration, resistivity, optical band gap, and transmittance.

Main Results:

• Work functions were tuned from 4.37 eV to 4.1 eV by controlling tungsten doping.
• Optimized IWO films (0-2.43 at.% W) demonstrated excellent TCO properties.
• Carrier concentration ranged from 8.39 x 10^19 cm^-3 to 8.58 x 10^21 cm^-3.
• Resistivity varied from 3.15 x 10^-4 Ωcm to 2.26 x 10^-3 Ωcm.
• Optical band gap ranged from 3.6 eV to 3.82 eV.
• Films with >2.43 at.% W showed >80% visible light transmittance.

Conclusions:

• Co-sputtering enables precise control over IWO work function and properties.
• Tungsten doping significantly enhances the performance of indium oxide as a TCO.
• Optimized IWOs are promising materials for transparent conductive applications in electronic devices.