Enhanced p-type conduction in AlGaN grown by metal-source flow-rate modulation epitaxy

Abstract

A metal-source flow-rate modulation epitaxy method is reported to enhance the hole concentration of Mg-doped AlGaN grown by metal organic chemical vapor deposition. The hole concentration of p-type AlGaN (Al content 0.43) is increased to 2.3 × 1017 cm−3 at room temperature by this method, which is about ten times higher than that of the conventional growth. The resistivity was found to be as low as 12.7 Ω·cm. Furthermore, the effective acceptor activation energy (EA) in the AlGaN films (Al content 0.32–0.43) was determined to be 20–22 meV, several times smaller than EA in p-GaN. Secondary ion mass spectroscopy measurements demonstrated that uniformly Mg-doped AlGaN structures with spatially modulated Al compositions were formed using this technique. It is suggested that the enhancement of hole concentration benefits from the modulation of the valence band edge.

Quantum engineering of non-equilibrium efficient p-doping in ultra-wide band-gap nitrides

“…4a ). The resistivity at 300 K is about 8.0 Ω cm, which is relatively lower compared to some recent results 30 , 31 . The E a can be estimated by based on the temperature-dependent resistivity, where ρ , T , ΔE , k B , and ρ 0 are the resistivity, temperature, E a , Boltzmann constant, and fitting coefficient, respectively 32 .…”

Deep-ultraviolet integrated photonic and optoelectronic devices: A prospect of the hybridization of group III–nitrides, III–oxides, and two-dimensional materials

“…To date, numerous efforts have been made to improve the con- ductivity property of the p-type Al x Ga 1−x N grown layers by increasing the hole concentration in magnesium-doped Al x Ga 1−x N and decreasing its acceptor activation energy. In spite of several approaches developed to overcome this obstacle, including magnesium-delta doping [180,416] , co-doping [417] , and polarization-induced doping [418] , these struc-tures involve wurtzite crystallographic orientations and suffer from high polarization effects, which result in even larger acceptor activation energies. During the Al x Ga 1−x N growth process, applying nitrogen-rich conditions with large V/III ratios is favorable to achieve better magnesium incorporation and smoother morphology structures.…”

Sec‐Eliminating the SARS‐CoV‐2 by AlGaN Based High Power Deep Ultraviolet Light Source

“…As an alternative to mercury lamps, AlGaN based UVC‐light‐emitting diodes (LEDs) present much higher power density, therefore are naturally suitable (already applied in some cases, e. g. water purification, air, and surfaces anti‐bacterial) for various disinfection purposes. [ 9–13 ] Although Nunayon et al. has confirmed the outstanding disinfection performance of UVC‐LEDs in impeding/extirpating indoor bioaerosol of influenza viruses H 1 N 1 and H 3 N 2 (who are also coronaviruses), which is competitive with mercury lamps, the direct experimental evidence reported for eliminating the SARS‐CoV‐2 with UVC is very limited, especially, there is no report for the ultra‐fast elimination.…”