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Nearest-neighbor configuration in (GaIn)(NAs) probed by x-ray absorption spectroscopy
Vincenzo Lordi1, Vincent Gambin, Stephan Friedrich
1Solid State and Photonics Laboratory, Stanford University, Stanford, California 94305, USA. vlordi@snow.stanford.edu
Physical Review Letters
|May 7, 2003
Summary
Annealing gallium indium nitride arsenide (Ga(1-x)In(x)N(y)As(1-y)) alloys causes indium (In) to segregate toward nitrogen (N) atoms. This atomic ordering stabilizes the material and shifts its emission wavelength.
Area of Science:
- Materials Science
- Semiconductor Physics
- Optoelectronics
Background:
- Gallium indium nitride arsenide (Ga(1-x)In(x)N(y)As(1-y)) is a key material for optoelectronic devices.
- The atomic structure and its effect on optical properties, especially the annealing-induced blueshift, remain unclear.
Purpose of the Study:
- Investigate the atomic arrangement in Ga(1-x)In(x)N(y)As(1-y) before and after annealing.
- Understand the relationship between atomic structure and the observed blueshift in emission wavelength.
Main Methods:
- X-ray absorption fine structure (XAFS) spectroscopy to probe the local chemical environment of nitrogen atoms.
- Ab initio simulations to model alloy stability and atomic ordering.
Main Results:
- As-grown Ga(1-x)In(x)N(y)As(1-y) exhibits a random atomic distribution.
- Post-annealing leads to the segregation of indium (In) atoms towards nitrogen (N) atoms, forming short-range order.
- This short-range ordering enhances thermodynamic stability.
Conclusions:
- The observed blueshift in emission wavelength after annealing is attributed to the In-N short-range ordering.
- This study clarifies the atomic mechanisms behind the optical properties of Ga(1-x)In(x)N(y)As(1-y) alloys.
- Findings contribute to the development of advanced optoelectronic components.