Effects of Different InGaN/GaN Electron Emission Layers/Interlayers on Performance of a UV-A LED

Abstract

In this study, we investigated the effects of InGaN/GaN-based interlayer (IL) and electron emitting layer (EEL) consisting of a GaN barrier layer grown with different metal-organic (MO) precursors of gallium (Ga), which were grown underneath the active layer. The growth behavior of GaN with triethyl Ga (TEGa) showed an increasing growth time due to a lower growth rate compared with GaN grown with trimethyl Ga (TMGa), resulting in the formation of columnar domains and grain boundary with reduced defect. UV-A light emitting diode (LED) chips with three types of ILs and EELs, grown with different MO sources, were fabricated and evaluated by light output power (LOP) measurements. The LOP intensity of UVLED-III with the GaN barrier layer-based IL and EEL grown by TEGa was enhanced by 1.5 times compared to that of the IL and EEL grown with TMGa at 300 mA current injection. Use of the GaN barrier layer in ILs and EELs grown by TEGa improved the crystal quality of the post grown InGaN/GaN multiple quantum well, which reduces leakage current. Therefore, for the UV-A LED with ILs and EELs grown with TEGa MO precursors, electrical and optical properties were improved significantly.

Effects of three-step magnesium doping in p-GaN layer on the properties of InGaN-based light-emitting diode

“…Therefore, the roughness increases as the amount of Mg atoms (Cp 2 Mg flow rates) increased. As reported, a high Cp 2 Mg flow rate can cause the polarity inversion in GaN and leads to surface roughness degradation (Kim et al , 2020). Simultaneously, the Mg doping can result in pyramidal-shaped extensive defects in the resultant GaN films when the Mg concentration exceeds 10 20 cm −3 (Ke et al , 2012b).…”

“…(002) or (102)]. The |b| is the magnitude of the Burgers vector for screw dislocation (5.19 × 10 −8 cm −2 ) and mixed-edge dislocation (3.19 × 10 −8 cm −2 ) (Christiansen et al , 1998; Abd Rahman et al , 2019; Kim et al , 2020). The FWHM of the GaN (002) and GaN (102) reflection planes is usually susceptible to screw and mixed-edge dislocation densities (Shang et al , 2015; Kim et al , 2020).…”

“…To date, conventional incandescent and compact fluorescent light bulbs were gradually phased out and replaced by white LEDs by converting the blue InGaN-based LEDs using yellow phosphor (Schubert and Kim, 2005). Many methods have been introduced to grow III-V single crystal, such as metal organic chemical vapor deposition (MOCVD) (Kim et al , 2020), molecular beam epitaxy (Tarief Elshafiey et al , 2020) and plasma-assisted MOCVD (Arifin et al , 2020).…”

Effects of V/III ratio of InGaN quantum well at high growth temperature for near ultraviolet light emitting diodes

“…GaN (10–12) FWHMs are 306, 309 and 313 arcsec for condition V/III ratios of 11824, 1419, and 20871, respectively. The FWHM of the GaN (0002) and GaN (10–12) reflection planes is usually susceptible to screw and mixed-edge dislocation densities (D. Kim et al , 2020; Shang et al , 2015). Using equation (1), the threading dislocation density (TDD) can be calculated as: where N denotes the TDD and β is the XRC FWHM [i.e.…”

“…However, compared to blue or green LEDs, NUV-LED has lower indium incorporation in the InGaN quantum wells (QWs), resulting in weak carrier localization and a small bandgap discontinuity at the interface between the InGaN QW and the GaN quantum barrier. As a result, in the MQWs of NUV-LEDs, there is less radiative recombination (Chang et al , 2003; Kim et al , 2020). The InGaN was found to be susceptible to growth conditions such as growth pressure, growth temperature, Si doping and growth termination (Han et al , 2003).…”