Realization of high efficiency AlGaN-based multiple quantum wells grown on nano-patterned sapphire substrates

Abstract

Growth of AlGaN-based multiple quantum wells (MQWs) with an IQE > 80% at room temperature has been realized on nano-patterned sapphire substrates. A DUV-LED device is then fabricated taking such high IQE MQWs as the active region.

The influences of AlGaN barrier epitaxy in multiple quantum wells on the optoelectrical properties of AlGaN-based deep ultra-violet light-emitting diodes

“…Sun et al reported the performance of DUV LED grown on nano-patterned sapphire substrates (NPSS) in combination with the optimization of V/III ratio and Si doping in MQWs. 48 They also found that the IQE of MQWs was improved from 56.2% to 70.3% when the V/III ratio was increased from 500 to 1000. However, further increasing V/III from 1000 to 2000 in MQWs slightly reduced the IQE from 70.3% to 69.2%.…”

“…Finally, we compared our results to several previous reports. [46][47][48] The ip-chip DUV LEDs with similar emission wavelengths are listed in Table 2. Zhang et al proposed a dislocation lter (DF) layer to improve the unfavourable stepbunching morphology of AlN layer grown at a high growth rate.…”

The stacking fault annihilation in a-plane AlN during high-temperature annealing

“…Currently, AlN-based DUV photoelectric devices are mainly fabricated on c-plane wurtzite AlN (c-AlN) because it is more mature to grow high-quality c-AlN on them than on other crystal planes. [1][2][3] However, there are strong spontaneous and piezoelectric polarization fields along the c-plane AlN, which can "tilt" the energy band and thus decrease the wavefunction overlap of the electron and hole carriers, which is named quantum-confined stark effect (QCSE). 4 The QCSE decreases the internal quantum efficiency and thus hinders the development of AlN-based light-emitting diodes (LEDs).…”

Optimizing metal/n-AlGaN contact by recessed AlGaN heterostructure with a polarization effect

“…In recent years, great progress has been made in the epi-growth and doping for AlGaN materials, thus boosting the development of AlGaN-based devices. [1][2][3] Owing to their superior intrinsic advantages including the tunable direct wide band-gap from 3.4 to 6.2 eV, high critical electric field, high electron saturation velocity, outstanding thermal and chemical stability, 4 AlGaN materials are essential in photoelectronic and electronic applications such as ultraviolet lighting, 5 sterilization, 6 environmental monitoring, 7 solar-blind communication, 8 power switching, 9 power conversion, 10 and RF amplifier. 11 Although previous reports on AlGaN-based devices have illustrated irreplaceable characteristics, one among the critical issues prevent further progress is the high-resistance contact.…”