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Surface-layer damage and responsivity in sputtered-ITO/p-GaN Schottky-barrier photodiodes

Publication Type:

Journal Article


Solid-State Electron. (UK), Volume 49, Number 12, p.1969 - 73 (2005)



carrier lifetime;carrier mobility;gallium compounds;III-V semiconductors;indium compounds;minority carriers;photodiodes;Schottky diodes;sputtering;


It is postulated that donor-like nitrogen vacancies, caused by the sputtering of a Schottky-barrier metal onto p-type gallium nitride, diffuse into the GaN and form a surface layer in which both the minority-carrier lifetime and mobility are drastically reduced. Such a damaged surface layer is shown to reduce the responsivity of p-GaN Schottky-barrier photodiodes, thereby offering an explanation for the responsivity values in the range of 0.03-0.04A/W that have been measured in experimental ITO/p-GaN devices. On making allowance for the damaged surface layer, an electron diffusion length of around 300nm can be inferred for the undamaged p-GaN region. [All rights reserved Elsevier]


surface-layer damage;sputtered-ITO Schottky-barrier photodiodes;p-GaN Schottky-barrier photodiodes;donor-like nitrogen vacancy;Schottky-barrier metal;p-type gallium nitride;minority-carrier lifetime;damaged surface layer;responsivity value;electron diffusion length;minority carrier diffusion length;InSnO-GaN;