Sputter-induced defects in Zn-doped GaAs Schottky diodes

Abstract

Schottky barrier diodes are made by ac magnetron deposition of Au on p-type GaAs substrates. Sputtering causes donor-like defects in the surface region of semiconductors, and these donor-like states compensate mostly the Zn shallow acceptor states over distances of 200 nm below the surface. These defects are attributed to the As Frenkel pairs V As -As i with an energy level at 0.27 eV below the conduction band. The As Frenkel pairs are responsible for the Fermi level pinning at metal-semiconductor interfaces and also for the observed change in barrier height in sputtered GaAs material.

Heteroepitaxial Growth of Gold Nanostructures on Silicon by Galvanic Displacement

“…13,42 Because the reaction is carried out at room temperature with the simplest of chemical apparatus (water, metal ion, substrate in a beaker), it is straightforward to carry out and is less expensive and faster than commonly used metal evaporation 52,53 and sputtering techniques. 5,54 Galvanic displacement has seen application in a number of different areas, particularly those related to the construction of nanoscale metallic and semiconductor architectures. For instance, Carraro and coworkers used galvanic displacement to produce gold nanoparticle catalyst arrays in silicon trenches for the synthesis of horizontally suspended silicon nanowires (NWs).…”

Preferential face deposition of gold nanoparticles on silicon nanowires by galvanic displacement

“…21,31,32 The deposition mechanism involves hole injection from metal ions into the semiconductor valence band followed by hole consumption via oxidation of semiconductor surface atoms, liberating bonding electrons for reduction of metal ions. 21 Hydrofluoric acid is required to ensure the dissolution of silicon in the form of soluble SiF 6 22 (aq) species according to eqn (1), and hence prevents the formation of an insulating silicon oxide product, inhibiting further metal ion reduction. Exposing H-terminated silicon nanowires to a 10 mL drop of 1 mM KAuCl 4 (aq) + 1% HF (aq) for 30 s resulted in the growth of gold nanoparticles of various shapes and sizes (in the range of about 20-30 nm), as revealed from the plan view scanning electron micrographs shown in Fig.…”

“…21 Galvanic displacement is a cost-effective method that requires merely a beaker containing an aqueous metal salt solution. This method is very convenient when compared to sputtering 22 and evaporation 23 methods.…”

Towards the epitaxial growth of silver on germanium by galvanic displacement

“…The result is metallic nanoparticles and films interfaced directly with the substrate surface. 15,16 Galvanic displacement was found to be advantageous over the commonly used metal evaporation 17 and sputtering techniques 18 in terms of its simplicity, cost effectiveness, and production of films of controlled morphology and crystalline orientation. 2,9,11,12,19 For instance, ultra high vacuum and annealing conditions are required for evaporated gold to align epitaxially on silicon surfaces, 20 while, in the case of galvanic displacement, heteropeitaxial growth of metallic nanostructures on various silicon surfaces such as Si(111), Si(100), and Si nanowires occurs at ambient conditions.…”