Formation of high-quality Ag-based ohmic contacts to p-type GaN

Low resistance and high reflectance ohmic contacts on p-type GaN were achieved using an Ag-based metallization scheme. Oxidation annealing was the key to achieve ohmic behavior of Ag-based contacts on p-type GaN. A low contact resistivity of similar to 5x10(-5) Omega cm(2) could be achieved from Me (=Ni, Ir, Pt, or Ru)/Ag (50/1200 angstrom) contacts after annealing at 500 degrees C for 1 min in O(2) ambient. Oxidation annealing promoted the out-diffusion of Ga atoms from the GaN layer, and Ga atoms dissolved in the in-diffused Ag layer with the formation of Ag-Ga solid solution, resulting in ohmic contact formation. Using Ru/Ni/Au (500/200/500 angstrom) overlayers on the Me/Ag contacts, the excessive incorporation of oxygen molecules into the contact interfacial region, and the out-diffusion and agglomeration of Ag, were effectively prevented during oxidation annealing. As a result, a high reflectance of 87.2% at the 460 nm wavelength and a smooth surface morphology could be obtained simultaneously. (C) 2008 The Electrochemical Society.open111618sciescopu

A Comparative Study Of Smartphone Addiction Drivers’ Effect On Work Performance In The U.S. And Korea

Smartphone addiction is a new phenomenon when a smartphone becomes a necessity in our daily life. This study explores smartphone addiction drivers and their results. Four factors such as ease of use, emotional lift, preference of social interaction, and flow, are used for drivers and neglect of work is used as a proxy of addiction result. In the result of structured equation modeling analysis, preference of social interaction is not related with smartphone usage behaviors such as usage frequency and usage hours. In the analysis of U.S. users, emotional lift is a driver and in the analysis of Korean users, ease of use and flow are drivers for smartphone addiction. There is a significant relationship between smartphone use and neglect of work in both countries. Even if there is a trend of converging user behavior because of globalization, drivers for smartphone addiction are different in the U.S. and Korea

The Effects Of Technology Readiness And Technology Acceptance On Nfc Mobile Payment Services In Korea

The Near Field Communication (NFC) mobile payment is the integration of NFC enabled smartphones and credit/debit/prepaid cards. Korea is a pioneer in rolling out the NFC mobile payment. Global mobile industries pay attention to whether Korean mobile users accept the new payment service. This study investigates the factors for technology acceptance using an integrated model of technology readiness and technology acceptance. Structured equation modeling is used to analyze the collected data. The four constructs of technology readiness (innovativeness, optimism, discomfort, and insecurity) have significant impact on the perceived ease of use and the two technological characteristics of NFC mobile payment (responsiveness and smartness) also have significant impacts on the perceived usefulness. However, only the perceived usefulness affects significantly on the intention to use. The perceived ease of use affects indirectly on the intention to use through the perceived usefulness. The result of this study suggests that to be a successful payment service, the NFC mobile payment service has to be much more focused on the usefulness against other alternative payment methods