Regulation And Study Of Carrier Injection Behavior In Deep-ultraviolet Luminescent Devices

In recent years,deep ultraviolet(DUV)short wavelength light-emitting diodes(LEDs)based on high A1 component AlGaN and its low-dimensional quantum structure have attracted great attention and have widely used in the fields of daily lighting,sterilization,smart home and light therapy.At present,although the international DUV-LED has made great research progress,but the overall device performance is still not high,the reason is that,in addition to the high Al component AlGaN crystal quality control and doping technology limitations,reasonable device structure is also very important,especially depending on the device structure of the longitudinal transport characteristics of carriers is a key factor to improve the deep UV LED device.This section focuses on the efficient carrier injection that high-performance DUV-LEDs must address,especially the injection behavior and regulation of cavities,and divided into the following areas:(1)AlGaN-based deep ultraviolet light-emitting diodes(DUV-LEDs)employing irregular H-shaped quantum barriers in the active region by modulating A1 composition has been investigated.It has been found that the H-shaped quantum barriers by insertion of double spike barriers with higher Al composition can effectively improve both the internal quantum efficiency(IQE)and light output power(LOP)compared to commonly adopted single-Al-composition barrier for AlGaN multiple quantum wells(MQWs).The concentration changes of electrons and holes in the active region due to the change of band structure are further studied,it is verified that the carrier transport in the deep ultraviolet LED devices using asymmetric H-shaped quantum barrier achieves a good balance,and the carrier compound rate in the quantum well is much higher than that of the common deep ultraviolet LED.(2)Improvement of carrier injection of AlGaN-based deep ultraviolet light-emitting diodes is studied with the combining of the well layer with the stepped p-AlGaN.Apsys is used for simulation calculate.It has been proved that the improvement of this novel approach is due to the decrease of electric field strength at both ends of AlGaN layer caused by polarization,which can give the function of ensuring high electron confinement and high hole injection at the same time,thus increasing the hole injection efficiency.That can significantly promote the radiative recombination in the active region.(3)Through the Apsys simulation software,the different gradient of Al components linear change electron blocking layer(EBL)structure are designed,the structure of Al component linear change electronic barrier layer(EBL)with different gradients was designed and compared with that of A1 component absolute linear change electronic barrier layer and common electronic barrier layer.The objective of the new structure design was to increase the effective barrier height of electrons,thus enhancing the electron binding in the multi-quantum well region.