Optoelectronic Properties of In(Ga)N/GaN and In(Ga)As/GaAs Ultra-Thin Quantum Wells

Student: Yurii Maidaniuk

Degree: Ph.D., December 2020

Major Professor: Dr. Gregory Salamo

Research Area(s):

Microelectronics

Photonics

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Background/Relevance

  • Aluminum and Gallium Nitride (AlN/GaN) offer opportunity for UV emitters, detectors, quantum computing, solar energy systems.

  • Wide band gap materials are also very important for high-power and high-frequency electronic devices.

  • Ultra-thin InGaAs/GaAs single QW is crucial to understand as being a building block of novel IR photodetectors.

Innovation

  • Fabrication of short period InN/InAs is one possible way to form a material with novel 2D properties to meet these needs.
  • We are currently successful at bringing new ideas to the growth, fabrication, and characterization of these novel materials.

Approach

  • InN/GaN multiple quantum well at different growth temperatures.
  • TEM cross-section demonstrating high quality interfaces.
  • Shown here: Photoluminescence is used to determine tunability.
  • Shown here: Time-resolved PL measurements of sub-monolayer In(Ga)As/GaAs structures to demonstrate strong lifetime dependence on In content.

Key Results

Results image for Yurii Maidaniuk; indium content profile and transition energy of InGaAs vs segregation coefficient

Conclusions

  • The optimal growth temperature has been found by analyzing PL data which is equal to 580 C.

  • The quantum well composition is determined to be InGaN instead of InN as was originally designed.  The equivalent result was obtained for In(Ga)As/GaAs QWs

  • We demonstrated the tunability of 2D wells which therefore can meet the intended applications

Future Work

  • Full analysis of the  TEM/STEM results on In(Ga)As/GaAs structures in order to prove segregation mechanism of QW formation.

  • Investigate how some of the parameters of growth change optical characteristics of the sample.