Choi Dae-Choul, Lee Seung Hun, Lee Sung-Nam
Department of IT Semiconductor Convergence Engineering, Tech University of Korea, Siheung 15073, Republic of Korea.
Materials (Basel). 2024 Jun 3;17(11):2700. doi: 10.3390/ma17112700.
We investigated a flat-type p*-p LED composed of a p*-electrode with a local breakdown conductive channel (LBCC) formed in the p-type electrode region by applying reverse bias. By locally connecting the p*-electrode to the n-type layer via an LBCC, a flat-type LED structure is applied that can replace the n-type electrode without a mesa-etching process. Flat-type p*-p LEDs, devoid of the mesa process, demonstrate outstanding characteristics, boasting comparable light output power to conventional mesa-type n-p LEDs at the same injection current. However, they incur higher operating voltages, attributed to the smaller size of the p* region used as the n-type electrode compared to conventional n-p LEDs. Therefore, despite having comparable external quantum efficiency stemming from similar light output, flat-type p*-p LEDs exhibit diminished wall-plug efficiency (WPE) and voltage efficiency (VE) owing to elevated operating voltages. To address this, our study aimed to mitigate the series resistance of flat-type p*-p LEDs by augmenting the number of LBCCs to enhance the contact area, thereby reducing overall resistance. This structure holds promise for elevating WPE and VE by aligning the operating voltage more closely with that of mesa-type n-p LEDs. Consequently, rectifying the issue of high operating voltages in planar p*-p LEDs enables the creation of efficient LEDs devoid of crystal defects resulting from mesa-etching processes.
我们研究了一种平面型p*-p发光二极管（LED），它由一个p电极组成，该电极在p型电极区域通过施加反向偏压形成了局部击穿导电通道（LBCC）。通过LBCC将p电极局部连接到n型层，应用了一种平面型LED结构，该结构无需台面蚀刻工艺即可替代n型电极。不含台面工艺的平面型p*-p LED展现出出色的特性，在相同注入电流下，其光输出功率与传统台面型n-p LED相当。然而，它们的工作电压较高，这归因于与传统n-p LED相比，用作n型电极的p区域尺寸较小。因此，尽管由于相似的光输出而具有相当的外部量子效率，但平面型p-p LED由于工作电压升高，其壁插效率（WPE）和电压效率（VE）降低。为了解决这个问题，我们的研究旨在通过增加LBCC的数量以扩大接触面积来降低平面型p*-p LED的串联电阻，从而降低总电阻。这种结构有望通过使工作电压更接近台面型n-p LED的工作电压来提高WPE和VE。因此，纠正平面p*-p LED中工作电压高的问题能够制造出没有因台面蚀刻工艺而产生晶体缺陷的高效LED。
