Yellow luminescence depth profiling on GaN epifilms using reactive ion etching

Abstract

Depth profiling measurements of photoluminescence on GaN epitaxial films grown on c-plane sapphire with metalorganic chemical vapor deposition have been performed. Dry etching technique of reactive ion etching is used with reactive gas of CCl2F2/H2/Ar under an operation power of 200 W. Before and after each etching, reflectivity and photoluminescence spectra are measured. Film thickness is determined from both the scanning electron microscopy and the interference oscillations of the reflectivity spectra. An excellent steady etching rate of 19.2 nm/min is established. The photoluminescence measurements show that both the near-band-edge and the yellow luminescence remain fairly constant until the film thickness of about 700 nm, and a large drop is obtained in the ratio of near-band-edge to yellow emission intensity under about 300 nm. Analysis shows that the yellow luminescence emitters are mostly confined within the near interface region, and supports the origin of yellow luminescence to be due to native defects instead of impurities.

Interface Effects on the Persistent Photoconductivity in Thin GaN and AlGaN Films

“…These values correlate well with the energy of the maximum of the yellow luminescence in photoluminescence (PL) measurements [9][10][11][12][13]. A recently published work on depth profiling of the yellow luminescence [14] also shows a strong increase in the ratio of yellow emission to near-band-edge emission near the interface. All these results strengthen the idea that the interface is important for the PPC.…”

X-ray and cathodoluminescence study on the effect of intentional long time annealing of the InGaN/GaN multiple quantum wells grown by MOCVD

“…For this YL emission, Kaufmann et al present the emission model derived from the recombination from the shallow Si donor level (30 meV) below the conduction band to a Sirelated deep acceptor level (1.08 eV) above the valence band [13]. However, it is still controversial whether the YL emission originates from intrinsic defects or from impurities [14][15][16][17]. The YL emission seems to be a universal feature, but it is seldom exhibited in good samples.…”

Electrical characterization of Au/n-GaN metal–semiconductor and Au/SiO2/n-GaN metal–insulator–semiconductor structures

“…This is due to their many good properties like the efficient, long-lasting light-emitting capability, especially in the visible range, the chemical stability, the mechanical strength and the high temperature endurance [1][2][3][4][5][6]. Recently, a number of GaN field-effect transistors (FETs) such as hetero-bipolar transistors, metal-oxide-semiconductor hetero-structure FETs and metal-insulator-semiconductor (MIS) FETs have been reported.…”