Fabrication and characterization of novel monolayer InN quantum wells in a GaN matrix

Abstract

Structural and optical characterization of InGaN/GaN multiple quantum wells grown by molecular beam epitaxyThe authors propose and demonstrate fine structure novel InN/GaN multiple quantum wells ͑MQWs͒ consisting of ultimately thin InN wells around 1 ML inserted in a GaN matrix grown under In-polarity growth regime by molecular beam epitaxy. Since the critical thickness of InN epitaxy on the c-plane GaN is about 1 ML and also the growth temperature for 1 ML InN insertion can be remarkably higher than conventional one, the proposed MQW structure can avoid new generation of misfit dislocation at the heterointerface, in principle, and results in high quality MQW structure due to the effects of enhanced surface migration at higher temperatures. It is shown that demonstrated 1 ML InN/GaN MQW structures indicate surprisingly higher structural quality/ properties than those former-reported InN-based heterostructures. Self-ordering mechanism arising from immiscibility nature in between InN and GaN will also contribute for depositing sharp and atomically flat InN well. The proposed MQW structure has physically and practically important meanings leading to room temperature operating GaN-based excitonic devices and also efficient photonic devices working in short wavelength visible colors.

1‐2 ML thick InN‐based quantum wells with InGaN barriers for blue‐green light emitters

“…Recently, we have proposed novel InN-based nanostructures consisting of atomically sharp and flat 1-2 monolayer (ML) thick InN quantum wells (QW) in GaN matrix/barriers [1][2][3]. The InN/GaN QW is expected to be a promising new active layer for high efficiency light emitters working in the UV, blue and up to green regions.…”

Nucleus and spiral growth mechanisms of nitride semiconductors in metalorganic vapor phase epitaxy

“…The results indicate that the InN growth is self-limited at higher T s 's of 590-620°C because of enhanced desorption of In and N adatoms from the growing surface. 36) At the highest T s 's (650-670°C), only 2D InN nuclei were observed on step-free GaN surfaces even for long t D of 180 s. It means that InN nucleus could not coalesce at these T s 's due to the extremely low growth rates. A summary of these results provided us a phase diagram of InN nucleation on a step-free GaN surface, which was plotted as a function of T s and t D in Fig.…”

Advances in InN epitaxy and its material control by MBE towards novel InN-based QWs

“…One of the most important findings for InN epitaxy is the big difference in the highest epitaxy temperatures of about 500 and 600 1C for In-polarity and N-polarity growth regimes, respectively [6,7]. These temperatures are critical ones where no film deposition is possible and only In droplets appears on the surface above them.…”

“…controlled MBE processes for better quality InN crystals under In-polarity and N-polarity growth regimes [6,7]. On the basis of understanding on the residual donors in unintentionally n-type doped InN, we have very recently achieved successful p-type doping of InN after a systematic and very wide range [Mg]s doping study [8][9][10][11][12][13].…”