Very high-efficiency semiconductor wafer-bonded transparent-substrate (AlxGa1−x)0.5In0.5P/GaP light-emitting diodes

Abstract

Data are presented demonstrating the operation of transparent-substrate (TS) (AlxGa1−x)0.5In0.5P/GaP light-emitting diodes (LEDs) whose efficiency exceeds that afforded by all other current LED technologies in the green to red (560–630 nm) spectral regime. A maximum luminous efficiency of 41.5 lm/W (93.2 lm/A) is realized at λ∼604 nm (20 mA, direct current). The TS (AlxGa1−x)0.5In0.5P/GaP LEDs are fabricated by selectively removing the absorbing n-type GaAs substrate of a p-n (AlxGa1−x)0.5In0.5P double heterostructure LED and wafer bonding a ‘‘transparent’’ n-GaP substrate in its place. The resulting TS (AlxGa1−x)0.5In0.5P/GaP LED lamps exhibit a twofold improvement in light output compared to absorbing-substrate (AS) (AlxGa1−x)0.5In0.5P/GaAs lamps.

The Promise and Challenge of Solid-State Lighting

“…The GaP wafer is attached to the AlInGaP heterostructure using wafer bonding at elevated temperature and pressure. 13 Forming the chip in the shape of a truncated inverted pyramid (TIP) further improves the extraction efficiency by minimizing the number of internal reflections-less light is absorbed, and more escapes from the device. 14 Figure 5 shows the TIP structure of the chip and also the external quantum efficiency of the device as a function of wavelength.…”

Highly selective dry etching of GaP in the presence of AlxGa1–xP with a SiCl4/SF6plasma

“…III-V materials are well established in the semiconductor industry for applications ranging from RF amplifiers in cellular communication devices to light emitting and laser diodes [1][2][3][4] to multi-junction concentrator solar cells [5,6]. The integration of such devices onto silicon substrates is an emerging trend, offering the opportunity to combine, for example, low-power opto-electronic devices [7][8][9] and highelectron-mobility transistors [10] based on III-V compound semiconductors with complex silicon microelectronic circuits.…”

Absorption and Light Scattering in InGaN-on-Sapphire- and AlGaInP-Based Light-Emitting Diodes

“…The most efficient one regarding extraction is the use of truncated inverted pyramids (TIPs) [3], [4]. It uses a structured thick window layer that serves as reflector.…”