Superlinear electroluminescence due to impact ionization in GaSb-based heterostructures with deep Al(As)Sb/InAsSb/Al(As)Sb quantum wells

Abstract

We report observation of superlinear electroluminescence in nanoheterostructures based on GaSb with a deep narrow Al(As)Sb/InAsSb/Al(As)Sb quantum well in the active region, grown by metal organic vapor phase epitaxy. Electroluminescent spectra were obtained for different driving currents at temperatures of 77 and 300 K. It is shown that such structure exhibits superlinear dependence of optical power on the drive current and its increase of 2-3 times. This occurs due to impact ionization in Al(As)Sb/InAsSb quantum well in which a large band offset at the interface DEc=1.27 eV exceeds ionization threshold energy for electrons in the narrow-gap well. Calculation of the size quantization energy levels is presented, and possible cases of impact ionization, depending on the band offset DEc at the interface and on the quantum well width, are considered. This effect can be used to increase quantum efficiency and optical power of light emitting devices (LEDs, lasers), as well as for photovoltaic elements.

Two-band superlinear electroluminescence in GaSb based nanoheterostructures with AlSb/InAs1−x Sbx/AlSb deep quantum well

“…Superlinear behavior of the EL and the power law dependence of the optical power on the drive current correspond well with the results obtained in our paper, 1 where the observed effects were explained by the contribution of the additional electron-hole pairs to the radiative recombination created due to the impact ionization by the electrons heated at the high energy different between AlAs conduction band offset and the first electron level E e1 in InAsSb QW (DE C À E e1 ).…”

“…This allows, according to the energy conservation law, the creation of a one electron-hole pair in the QW with a width of 5 nm: at T ¼ 300 K (DE C À E e1 ) ¼ 0.884 eV, and at T ¼ 77 K (DE C À E e1 ) ¼ 0.931 eV. 1 This effect can be considered as an inverse Auger recombination process. 7 This work reports the study of the superlinear EL in nanoheterostructures with deep AlSb/InAs 1Àx Sb x /AlSb QWs grown on n-GaSb substrate by MOVPE.…”

Enchancemnt of the optical power stimulated by impact ionization in GaSb-based heterostructures with deep quantum wells

“…25 The time of energy relaxation of hot electrons to the first level and the time of impact ionization are much shorter (<10 -11 -10 -12 s) than the radiative recombination time (<10 -8 -10 -9 s). Due to this fact additional electrons produced by impact ionization process will be accumulated on the E e1 quantum-size level and radiatively recombine with holes.…”

“…5). 25 We have also considered the dependence of the impact ionization intensity on the width of the quantum well d. For room temperature three situations are possible: a) 4.2 nm < d < 6.6 nm: energy conservation law allows one electron-hole pair to be created, because the following condition is fulfilled:…”

Вертикальный транспорт в гетеропереходах II типа с композитными квантовыми ямами InAs/GaSb/AlSb в сильном магнитном поле

“…• C. Sb-интерфейс между КЯ InAs и GaSb был реализован при специальном переключении металло-органики [23,24]. На подложке n-InAs(100), легирован-ной Mn, с концентрацией ∼ 5 · 10 16 см −3 , выращивались буферный слой GaSb толщиной 30 нм и две КЯ с размерами 12.5 нм (InAs) и 8 нм (GaSb), ограниченные двумя барьерами AlSb толщиной по 30 нм.…”