Plasma assisted molecular beam epitaxial growth of GaN with low growth rates and their properties

Abstract

A systematic investigation on PA-MBE grown GaN with low growth rates (less than 0.2 µm/h) has been conducted in a wide growth temperature range, in order to guide future growth of sophisticated fine structures for quantum device applications. Similar to usual growths with higher growth rates, three growth regions have been revealed, namely, Ga droplets, slightly Ga-rich and N-rich 3D growth regions. The slightly Ga-rich region is preferred, in which GaN epilayers demonstrate optimal crystalline quality, which has been demonstrated by streaky RHEED patterns, atomic smooth surface morphology, and very low defect related yellow and blue luminescence bands. The growth temperature is a critical parameter to obtain high quality materials and the optimal growth temperature window (~ 700–760 °C) has been identified. The growth rate shows a strong dependence on growth temperatures in the optimal temperature window, and attention must be paid when growing fine structures at a low growth rate. Mg and Si doped GaN were also studied, and both p- and n-type materials were obtained.

Nonequilibrium electron–phonon coupling across the interfaces between Al nanofilm and GaN

“…At present, the main preparation methods of GaN include metal–organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), 32 hydride vapor-phase epitaxy (HVPE), 33 and ammonothermal method. 34 GaN (0001) substrate used in this work is prepared in a standard pressure (MOCVD) reactor using trimethylgallium and NH 3 as Ga and N precursors, and H 2 is the carrier gas.…”

Step-flow growth of Al droplet free AlN epilayers grown by plasma assisted molecular beam epitaxy

“…The crystalline quality of MBE grown AlN is mainly affected by Al/N ratios and growth temperatures. Similar to the GaN MBE growth diagram [10,11], the AlN MBE growth diagram is also divided into three growth regions: N-rich, intermediated Al-rich and Al-droplet, when varying different Al/N ratios and growth temperatures [12]. AlN epilayers grown in the N-rich region are characterized by rough threedimensional (3D) surface morphology and poor crystal quality.…”