Formation of ohmic contacts to p‐type ZnO

Abstract

Formation of ohmic contacts to p-type zinc oxide (ZnO) was studied. The p-type ZnO samples were grown by metalorganic molecular-beam epitaxy with diethylzinc, deionized water vapor and monomethylhidrazine and were annealed under oxygen gas ambient at 650 °C or 700 °C for 20 min to activate doped nitrogen acceptors. Although the current-voltage characteristics measured through gold p-contacts were not perfectly ohmic, they showed perfectly ohmic properties after rapid thermal annealing (RTA) in the temperature range of 300 to 520 °C for 2 min. The ohmic contact resistivity was measured with the transmission-line measurement method and it was decreased to approximately 1/64 with increasing the RTA temperature. The minimum contact resistivity of 3.15 × 10 -3 Ω cm 2 was observed with RTA at 520 °C for 2 min.

Surface termination and Schottky-barrier formation of In4Se3(001)

“…Ohmic metallization versus Schottky rectifying behavior of metal contacts at the surface of semiconductors is complicated and depends on many factors such as the type of contact material, the pre-and post-annealing procedures, the number of layers of the contacts (single, bilayer, multilayer), and even the thickness of the layer(s) [49][50][51][52]. Au is a widely used material for device contacts and figure 4 shows the evolution of the In 3d 5/2 core level components, for In 4 Se 3, with increasing Au adlayer thickness.…”

High-Quality ZnO Thin Films Grown by Fast Pulsed Laser Deposition without a Buffer Layer

“…The Hall properties of ZnO films were studied by the standard four-point Van der Pauw technique, in which the Ohmic contact was achieved using annealed Au electrodes. 16,17) The typical intrinsic ZnO film prepared by PLD is of the n-type with a carrier concentration of 10 18 cm À3 , a resistivity on the order of 10 À1 cm, and an electron mobility of 10 cm 2 /V s due to various defects. 4,6) ZnO films grown by FPLD achieve a high mobility up to 100 cm 2 /V s at 300 K with a carrier concentration in the range from 2 to 5 Â 10 16 cm À3 , indicating that the number of intrinsic defects of the films can be reduced by FPLD.…”