Low resistance indium tin oxide contact to n-GaAs nanowires

Indium tin oxide (ITO) was deposited by RF sputtering on n-GaAs nanowires grown by the Au-assisted vapor-liquid-solid process in a molecular beam epitaxy (MBE) system. The ITO formed an Ohmic contact with n-doped (n = 8 x 10(18) cm(-3)) GaAs nanowires with a specific contact resistance of <1.41 Omega cm(2). Insertion of a 25 nm thick indium layer between 500 nm thick ITO and the GaAs nanowires resulted in a reduction of specific contact resistance to <0.13 Omega cm(2) after annealing at 400 degrees C for 30 s. The In/ITO film had an average transmittance of 89% from 400 to 900 nm and a sheet resistance of 13 Omega/square, which is well suited for nanowire-based optoelectronic applications.