Search results

Sort By:

Limit search:

Luminescence of Highly Excited Nonpolar a-Plane GaN and AlGaN/GaN Multiple Quantum Wells

100%

Juršėnas S., Kuokštis E., Miasojedovas S., Kurilčik G., Žukauskas A., Chen C., Yang J., Adivarahan V., Asif Khan M.

Acta Physica Polonica A

2004

vol. 105

issue 6

567-573

Carrier recombination dynamics in polar and nonpolar GaN epilayers and GaN/AlGaN multiple quantum wells grown over sapphire substrates with various crystallographic orientation were studied under high photoexcitation by 20 ps laser pulses. The transient of luminescence featured a significant enhancement in nonradiative recombination of free carriers for nonpolar a-plane GaN epilayers compared to conventional c-plane samples. The epitaxial lateral overgrowth technique was demonstrated to significantly improve the quality of nonpolar a-plane films. This was proved by more than 40-fold increase in luminescence decay time (430 ps compared to ≤10 ps in the ordinary a-plane epilayer). Under high-excitation regime, a complete screening of built-in electric field by free carriers in multiple quantum wells grown on c-plane and r-plane sapphire substrates was achieved. Under such high excitation, luminescence efficiency and carrier lifetime of multiple quantum wells was shown to be determined by the substrate quality.

Luminescence of Highly Photoexcited GaN Epilayers and Heterostructures Grown on Different Sapphire Crystal Planes

100%

Juršėnas S., Miasojedovas S., Kurilčik G., Liuolia V., Žukauskas A., Chen C., Yang J., Kuokštis E., Adivarahan V., Asif Khan M.

Acta Physica Polonica A

2005

vol. 107

issue 2

235-239

GaN epilayers and AlGaN/GaN multiple quantum wells grown by metalorganic chemical vapor deposition on different crystal planes (c, a, and r) of the sapphire substrate were studied by excitation intensity dependent and time-resolved photoluminescence. In polar multiple quantum wells grown on a- and c-planes, a blueshift of the luminescence band with increasing the excitation energy was observed, indicating that screening of built-in field by free carriers takes place, whereas in nonpolar r-plane grown multiple quantum wells, the luminescence band maintained an almost constant peak position. Full screening of built-in field was achieved at the excitation densities higher than 0.3 mJ/cm^2. Under conditions of screened built-in electric field the structures were characterized by carrier lifetime. It was shown that nonpolar multiple quantum wells suffer from high density of nonradiative traps that can be due to substrate related threading dislocations.

Refine search results

2 Acta Physica Polonica A

1 2005

1 2004

2 Adivarahan V.

2 Asif Khan M.

2 Chen C.

2 Juršėnas S.

2 Kuokštis E.

2 Kurilčik G.

2 Miasojedovas S.

2 Yang J.

2 Žukauskas A.

1 Liuolia V.

Search results

Luminescence of Highly Excited Nonpolar a-Plane GaN and AlGaN/GaN Multiple Quantum Wells

Luminescence of Highly Photoexcited GaN Epilayers and Heterostructures Grown on Different Sapphire Crystal Planes