Characteristics of an AlGaInP-Based Light Emitting Diode With an Indium-Tin-Oxide (ITO) Direct Ohmic Contact Structure

A tantalum diffusion barrier layer for improving the output performance of AlGaInP-based light-emitting diodes

“…5,6) However, a large difference in refractive index between GaP (n = 3.20) 7) and air (n = 1.0) significantly hinders the escape of light generated in the active region, resulting in low light extraction efficiency (LEE). To enhance the LEE, different methods, such as the use of indium tin oxide (ITO) 4,[8][9][10][11] and Al-doped ZnO (AZO) 12) with intermediate refractive indices and surface texturing 13,14) have been used. For example, Liu et al 8) investigated the performance of AlGaInP-based LEDs with an ITO transparent film and a Be-diffusion process, reporting that the LEDs showed 27% higher external quantum efficiency (EQE) at 100 mA than conventional LEDs without the ITO film.…”

“…To enhance the LEE, different methods, such as the use of indium tin oxide (ITO) 4,[8][9][10][11] and Al-doped ZnO (AZO) 12) with intermediate refractive indices and surface texturing 13,14) have been used. For example, Liu et al 8) investigated the performance of AlGaInP-based LEDs with an ITO transparent film and a Be-diffusion process, reporting that the LEDs showed 27% higher external quantum efficiency (EQE) at 100 mA than conventional LEDs without the ITO film. Furthermore, Lee et al 13) investigated the effect of surface texturing and a backside-patterned reflector on the performance of AlGaInP LEDs, showing that the light trapped inside the LED chip was efficiently extracted from the roughened surface of the LEDs.…”

“…So far, different types of metal schemes have been examined to form high-quality ohmic contacts, including ITO, Pd=Zn=Pd, Pd=In, In, and Au=Be= Au. 4,[8][9][10][11][15][16][17][18][19][20][21][22][23] For example, Lo et al 4) investigated the electrical properties of ITO transparent contacts to p-GaP for AlGaInP-based LEDs, demonstrating that the ITO contact had a specific contact resistance of 1.57 × 10 −4 Ω•cm 2 when annealed at 400 °C for 5 min in N 2 ambient and a transmittance of 90% in the wavelength range, 400-700 nm. Consequently, the AlGaInP-based LEDs with the 400 °Cannealed ITO contacts produced an output power of 6.0 mW at 20 mA.…”

Measuring the thermal resistance of LED packages in practical circumstances

“…In recent years, due to rapid development of high power LEDs, thermal management and heat dissipation become essential [1][2][3]. For the LED modules with the electric power up to 120 W, since large amount of heat is generated, the thermal problem is a bottleneck to limit their lifetime and optical properties [4].…”

Postannealing Effect on ITO/p+-GaP with a Diffused Layer

“…Indeed, W. C. Liu et al have proposed the concept of ITO/p-GaP direct ohmic contact structure. 16 However, the further study in post-ITO annealing at different temperatures and the contact mechanisms of ITO/p-GaP have not been investigated. In this study, we report the conversion of p-GaP layer into p þ -GaP layer and study the post-ITO-deposition annealing temperature effects on the contact mechanisms of ITO/p-GaP.…”