A Comprehensive Study on Mo/CdTe Metal-Semiconductor Interface Deposited by Radio Frequency Magnetron Sputtering

Area of Science:

• Materials Science
• Solid State Physics
• Renewable Energy

Background:

• The metal-semiconductor (MS) junction is critical for CdTe solar cell performance.
• Understanding the Mo/CdTe interface is essential for optimizing CdTe-based photovoltaics.

Purpose of the Study:

• Investigate the impact of different substrates on the Mo/CdTe MS junction.
• Characterize the formation and properties of MoTe2 at the Mo/CdTe interface.

Main Methods:

• Thin film deposition of Mo/CdTe on polyimide (PI) and soda lime glass (SLG) substrates.
• X-ray Diffraction (XRD) for structural analysis and preferred orientation.
• Energy-Dispersive X-ray (EDX) spectroscopy for elemental composition.
• Transmission Electron Microscopy (TEM) for nanostructure and lattice constant determination.
• Hall effect measurements for bulk carrier concentration and type determination.

Main Results:

• XRD revealed preferential (100) orientation of MoTe2 on PI substrates, diminishing with increased CdTe deposition time.
• EDX confirmed MoTe2 formation at the Mo/CdTe interface on PI, absent on SLG.
• Bulk carrier concentration on PI was initially high (1.42 x 10^18 cm^-3), decreasing with CdTe growth.
• Unintentionally formed MoTe2 on PI was n-type.
• TEM provided lattice constants for CdTe (a = 6.5 Å) and MoTe2 (a = 3.52 Å).

Conclusions:

• Substrate choice significantly influences the Mo/CdTe interface and MoTe2 formation.
• The presence and type of MoTe2 on PI substrates affect carrier concentration in Mo/CdTe films.
• Findings provide insights into optimizing MS junctions for CdTe solar cells.