In this study, changes in the activation energy of donors and carrier concentration in n-type GaN (n-GaN) samples, due to (NH4) 2Sx treatment, were investigated. We find that the activation energy of Si in the n-GaN samples without or with (NH 4)2Sx treatment was determined to be 21 meV and a donor level was also present in (NH4)2S x-treated n-GaN near the surface with an activation energy of 59 meV which is associated with sulfur donors substituting for nitrogen. By rearranging the well-known equations for the conductivity and mobility in two-layer systems, we find that the electron concentration within the thin sulfur-passivated layer in n-GaN near the surface at room temperature increased from its original value 6.9 × 1017 cm-3 to 9.7 × 1019 cm-3, resulting in the occurrence of the Burstein-Moss shift for optical band-gap observation.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering
- Materials Chemistry