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In this work, we present the investigation of InN/GaN multiple-quantum-well (MQW) growth by plasma-assisted molecular beam epitaxy using in-situ reflection high-energy electron diffraction (RHEED) to monitorthe growth process. The analysis of the RHEED intensity and pattern transitions identified an indium surface ac-cumulation even with a nominal thickness of InN as small as 0.5 monolayer (ML). This result explicitly showsthat, even at low growth temperaturesof ~550 °C, not all of the supplied indium isincorporated into the quantumwell (QW). Moreover, the residual indium can become incorporated into the GaN matrix on either side of theQW. Both QW thickness and the photoluminescence (PL) emission energy showed a self-regulating behavior.The apparent thickness did not exceed 2 MLs even when the deposited InN thickness is as large as 5 MLs. ThePL emission shows a continuous redshift with the deposited InN from ~370 nm for 0.5 ML until it saturates at~423 nm forN2 ML. Based on the observed growth phenomena, a qualitative growth model was developed to ex-plain the self-limited epitaxial growth of ultrathin In(Ga)N/GaN QWs
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This content will become publicly available on April 14, 2026
Stabilization of III-nitrides at high temperatures using nitrogen plasma
III-Nitride materials such as gallium nitride (GaN) and indium nitride (InN) are critical for applications in electronics and optoelectronics due to their exceptional properties. However, their high-temperature stability is often limited by decomposition into constituent elements at low nitrogen pressures near or below ambient. This work investigates the use of nonequilibrium nitrogen plasma to stabilize GaN and InN at elevated temperatures and low pressures. Bulk nitride synthesis was demonstrated via plasma-assisted nitridation of Ga and In metals. Following synthesis, the suppression of nitride decomposition at temperatures exceeding the predicted equilibrium limits was accomplished by means of a nonequilibrium nitrogen plasma. Experimental results revealed that the nonequilibrium plasma imparted an additional chemical potential onto the ground state nitrogen by electron impact excitation, stabilizing GaN at 1000 °C and InN at 600 °C for nitrogen partial pressures as low as 10 Pa. With this experimental approach, the chemical potential of excited nitrogen species in the plasma was estimated to be 1.8 eV higher than the ground state value. These findings highlight the potential for plasma-based processing to enable scalable synthesis and stabilization of III-nitrides at high temperatures for advanced material applications.
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- Award ID(s):
- 1847469
- PAR ID:
- 10637370
- Publisher / Repository:
- American Institute of Physics
- Date Published:
- Journal Name:
- Applied Physics Letters
- Volume:
- 126
- Issue:
- 15
- ISSN:
- 0003-6951
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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