In-situ photoluminescence monitoring of GaN in plasma exposure

In situmeasurement of GaN film photoluminescence under plasma etching

“…It can be seen that both Ar and N 2 plasma etchings induce significant decreases in the NBE peak and YL intensities, which is similar to the findings of a previous study [10,11]. To be precise, after Ar plasma etching, the NBE peak intensity drops by 78% while the YL intensity decreases by 84%.…”

“…Negative high-voltage pulses (referred to below as bias voltages) are introduced and repetitively applied to the target. This is different from the condition we used before [10][11][12]. Here, it should be pointed out that when the bias is introduced, strong emissions from the plasma increase several times compared to those reported in Refs.…”

“…[10] and [11]. As a consequence, the weak luminescence from the GaN films is surrounded by, and can be hardly distinguished from, the total luminescence with the naked eye.…”

“…In our previous studies, GaN film photoluminescence (PL) was probed in situ under no-bias plasma condition [10][11][12]. In this article, we further improve the method, which enables us to measure in situ the GaN film PL under Ar or N 2 plasma etching with *Corresponding authors.…”

Effect of UV Irradiation on Ar-Plasma Etching Characteristics of GaN

“…For the GaN sample etched without the UV irradiation, large decreases in BE, YL, and BL intensities can be seen compared to those of the as-grown GaN, which suggests numerous non-radiative point defects are generated in the bulk regions (∼70 nm) by the Ar-plasma etching. 6,14,15 On the other hand, a significant increase in BE intensity with further decreases in YL and BL intensities can be seen for the GaN sample etched with the UV irradiation. In addition, the half width at half maximum (HWHM) of the BE peak of the GaN etched with the UV irradiation is larger than those of the as-grown GaN and the GaN etched without the UV irradiation, as shown in Fig.…”