Semipolar III-nitride laser diodes with zinc oxide cladding.

Area of Science:

• Semiconductor Physics
• Optoelectronics
• Materials Science

Background:

• Transparent conducting oxides (TCOs) are crucial for III-nitride laser diodes (LDs).
• Indium tin oxide (ITO) is commonly used but has limitations.
• Optimizing TCOs can improve device performance and fabrication.

Purpose of the Study:

• To investigate zinc oxide (ZnO) as an alternative TCO top cladding in semipolar (202¯1) III-nitride LDs.
• To evaluate the impact of ZnO on optical loss and device performance compared to ITO.
• To demonstrate lasing in a ZnO-clad semipolar III-nitride LD.

Main Methods:

• Numerical modeling to assess optical absorption and internal loss.
• Fabrication of semipolar (202¯1) III-nitride LDs with ZnO top cladding.
• Characterization of lasing performance, including threshold current density and voltage.

Main Results:

• Numerical simulations predicted lower optical absorption for ZnO compared to ITO.
• Lasing was successfully achieved in the ZnO-clad semipolar III-nitride LD.
• The device exhibited a threshold current density of 8.6 kA/cm² and a threshold voltage of 10.3 V at 453 nm.

Conclusions:

• ZnO is a viable alternative TCO for III-nitride LDs, offering reduced internal optical loss.
• The use of ZnO simplifies fabrication by lowering growth temperature and time for p-type layers.
• This study demonstrates the potential of ZnO for efficient semipolar III-nitride laser diode applications.