Fabrication of indium tin oxide bump/pit structures on GaN-based light emitting diodes

Abstract

In the past several decades, significant progress has been made to improve the performance of semiconducting light emitting diodes (LEDs), which has resulted in a wide number of applications for LEDs in the information and energy fields. However, light extraction efficiency is limited due to remarkable total internal reflection on the device's surface due to the large refractive index of GaN and indium tin oxides (ITO). In this work, ITO bump and pit patterns were fabricated on the LED surface using an ion beam etching method via metal or resist masks, respectively. By changing the incident angle of the ion beam and the material of the masks, the effects of faceting and redeposition can be properly controlled, resulting in well-controlled manipulation of the shape of the fabricated bump/pit structures. By altering the etching time, the over-etched structures have a much smoother surface compared with the under-etched/in-etched structures. These bump/pit structures could have potential applications in LED light emitting enhancement and optical devices.

Studies of Catalytic Materials with In Situ Transmission Electron Microscopy

“…77 This is especially noticeable in the case of Ostwald ripening, which will be discussed in more detail in Chapter 4, where OR is discussed in more detail and where in situ TEM is used to follow the OR of Au nanoparticles supported on TiO2 in an aqueous phase. 79 In electron microscopy, the sample is illuminated with a beam of high energy electrons, which interact with the sample in many ways, as shown in Figure 1.6c. These interactions produce all kinds of signals that can be detected with the appropriate detectors and detector locations, each of which then provides different information about the specimen.…”

“…The scale bar corresponds to 500 nm. The image in (a) was acquired by Liu et al and reproduced with permission 79.…”