Photoluminescence Spectroscopy as a Tool for Quality Control of GaN Thin Film to Be Used in Solar Cell Devices

Abstract

The use of III-V and semiconductor nitrides in solar cells has been of interest in the PV-community due to the wide variation range of the band gap in these materials. Particularly, the processing of hetero-junction structures of InGaN/GaN and Si(p)/GaN(n) has been of great interest recently. In this work, the quality of GaN and InGaN thin films grown by Molecular Beam Epitaxy (MBE) on different substrate and buffer layers has been studied by photoluminescence spectroscopy (PL). The PL measurements were processed as function of sample temperature and pump power. In the PL spectra it is possible to observe a strong near band-gap-edge emission and a broad blue, green and yellow luminescence (BL, GL, YL), which can be assigned to the presence of Ga and N vacancies, amorphous phases, deep level impurities and structural defects. The relative intensity between the different peaks of the bands related to defects or impurities was studied as a tool for quality control of the films.

Metal nitride-based nanostructures for electrochemical and photocatalytic hydrogen production

“…The target absorbs the energy, which subsequently excites its electrons [ 165 ]. Pau et al [ 166 ] and Rodríguez et al [ 167 ] successfully fabricated high-quality AlGaN and InGaN thin film with advanced photoresponse via MBE, respectively, indicating a bright future on epitaxial growth of mix-MNs. Tsuji et al utilized an rf-plasma-assisted MBE system to represent a promising synthesis route for stabilized CaZn 2 N 2 epitaxial films, as presented in Figure 7e [ 168 ].…”

Long-range ordered vertical III-nitride nano-cylinder arrays via plasma-assisted atomic layer deposition

“…On the other hand, a weak and noisy signal was observed from B60 nm thick GaN thin films which exhibited two relatively weaker peaks at 371.3 nm (3.34 eV) and 500 nm (2.48 eV), most probably originating from a red shifted band-edge-related emission and structural defect sourced ''green luminescence (GL)'', respectively. 95,96 The presence of the ''GL'' band could be explained by the combination of gallium vacancy clusters and oxygen (or carbon) impurities. 96 GaN HNCs exhibit a stronger PL signal than their thin-film counterparts possibly due to their higher surface to volume ratio.…”

“…95,96 The presence of the ''GL'' band could be explained by the combination of gallium vacancy clusters and oxygen (or carbon) impurities. 96 GaN HNCs exhibit a stronger PL signal than their thin-film counterparts possibly due to their higher surface to volume ratio.…”