BAlGaN alloys nearly lattice-matched to AlN for efficient UV LEDs

MBE-grown 232-270 nm Deep-UV LEDs using Monolayer thin Binary GaN/AlN quantum heterostructures

Electrically injected deep ultra-violet (UV) emission is obtained using monolayer (ML) thin GaN/AlN quantum structures as active regions. The emission wavelength is tuned by controlling the thickness of ultrathin GaN layers with monolayer precision using plasma assisted molecular beam epitaxy (PAMBE). Single peaked emission spectra is achieved with narrow full width at half maximum (FWHM) for three different light emitting diodes (LEDs) operating at 232 nm, 246 nm and 270 nm. 232 nm (5.34 eV) is the shortest EL emission wavelength reported so far using GaN as the light emitting material and em…

Compatibility of the selective area growth of GaN nanowires on AlN-buffered Si substrates with the operation of light emitting diodes

AlN layers with thicknesses between 2 and 14 nm were grown on Si(111) substrates by molecular beam epitaxy. The effect of the AlN layer thickness on the morphology and nucleation time of spontaneously formed GaN nanowires (NWs) was investigated by scanning electron microscopy and line-of-sight quadrupole mass spectrometry, respectively. We observed that the alignment of the NWs grown on these layers improves with increasing layer thickness while their nucleation time decreases. Our results show that 4 nm is the smallest thickness of the AlN layer that allows the growth of well-aligned NWs with…

Fabrication technology for high light-extraction ultraviolet thin-film flip-chip (UV TFFC) LEDs grown on SiC

The light output of deep ultraviolet (UV-C) AlGaN light-emitting diodes (LEDs) is limited due to their poor light extraction efficiency (LEE). To improve the LEE of AlGaN LEDs, we developed a fabrication technology to process AlGaN LEDs grown on SiC into thin-film flip-chip LEDs (TFFC LEDs) with high LEE. This process transfers the AlGaN LED epi onto a new substrate by wafer-to-wafer bonding, and by removing the absorbing SiC substrate with a highly selective SF6 plasma etch that stops at the AlN buffer layer. We optimized the inductively coupled plasma (ICP) SF6 etch parameters to develop a s…

体AlN衬底上InGaN帽层AlGaN基深紫外LED工作电压的改善

Improved operating voltage in InGaN-capped AlGaN-based DUV LEDs on bulk AlN substrates

本研究针对深紫外LED需同时实现低阻p、n型接触的难题，通过在n型接触高温退火前沉积PE-ALD SiO₂帽层保护p-InGaN层，成功制备出工作电压降低3.5V的268nm深紫外LED，为高Al组分AlGaN器件提供可规模化制备路径。

Al-rich AlGaN合金中Dopability限制的研究

Dopability limits in Al-rich AlGaN alloys for far-UVC LEDs

研究Al-rich AlGaN合金中载流子注入限制问题，通过分析点缺陷揭示合金建模和带隙温度依赖性的重要性，发现Si掺杂形成补偿负U DX中心，碳是主要杂质，影响n型导电性。