[E-1] Emerging Thin Film Devices and Technologies

[E-1-03] Optical Properties of C-axis Oriented Polycrystalline GaN Thin Layer on Si (001) substrate grown by RF-MBE

〇Shyun Koshiba¹, Takeshi Kuraoka¹, Kazuhiro Morishita¹, Hidefumi Akiyama², Naoshi Takahashi³, Hayato Miyagawa¹, Yasuhiro Tanaka¹ (1. Kagawa University (Japan), 2. Univ. of Tokyo (Japan), 3. Kagawa University (Japan))

Presentation style: Online

https://doi.org/10.7567/SSDM.2022.E-1-03

Optical properties of c-axis oriented polycrystalline GaN on the Si (001) substrates formed by plasma assisted molecular beam epitaxy were studied. Light emission near the band edge of polycrystalline GaN was observed by PL measurement at room temperature. From the red shift of the peak and the size of the peak width, the effects of lattice strain with the Si substrate and grain boundaries, on fluctuation in the GaN bandwidth were clarified. As a result of Voigt function fitting of the PL spectrum at 77K, it was clarified that there are three energy levels related to the GaN near band edge and crystalline defects.

Results of room temperature PL measurement of samples with GaN layers of different thickness and sam-ples with an AlN barrier layer in between GaN and Si substrate, thickness of the surface depletion layer of the c-axis oriented polycrystalline GaN is smaller than 20 nm, while the thickness of the depletion layer from the GaN / Si interface is between 20 nm and 100 nm.