Photoconduction of p-type Ultrananocrystalline Diamond/Hydrogenated Amorphous Carbon Composite Films in Metal-Semiconductor-Metal Geometry
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2016-09-01 |
| Journal | ECS Meeting Abstracts |
| Authors | Takanori Hanada, Shinya Ohmagari, Abdelrahman Zkria, Tsuyoshi Yoshitake |
| Institutions | National Institute of Advanced Industrial Science and Technology |
Abstract
Section titled āAbstractāPhotovoltaics are representative renewable energy devices and the development of the next-generation photovoltaics have attracted considerable attentions. Ultrananocrystalline diamond (UNCD)/hydrogenated amorphous carbon (a-C:H) composite (UNCD/a-C:H) films, which possess large absorption coefficients of more than 10 6 cm ā1 at photon energy range between 3 and 6 eV is one of the candidate materials to be employed as photovoltaic devices. It has been theoretically predicted that additional energy states are introduced between the bandgap of diamond owing to a large amount of GBs. Here, GBs denote interfaces between UNCD grains and those between UNCD grains and an a-C:H matrix. Doped impurity atoms are preferentially incorporated into GBs. As a result, the production of p-type and n-type conduction with enhanced electrical conductivities is realized by boron (B) and nitrogen (N) doping, respectively. Thus far, p-type UNCD/a-C:H films were deposited on n-type Si substrates, and it was confirmed that they exhibit typical rectifying behaviors. The UNCD/a-C:H films certainly act as drift layers in heterojunction diodes. Moreover, our recent studies have experimentally proved that UNCD/a-C:H can detect deep-ultraviolet (DUV) light with high external quantum efficiencies and the detectivity for 254 nm monochromatic light was enhanced at low temperatures. As for the photodetection of UNCD/a-C:H, spectral photoresponse measurements suggests that localized mid-gap states act as the generation centers of photocarriers. Although the peculiar photodetection properties might be attributable to GBs, the details were unknown. In this study, the photovoltaic characteristics of UNCD/a-C:H films are experimentally demonstrated. The photovoltaic characteristics of UNCD/a-C:H films are discussed on the basis of photoconduction spectroscopic analysis data.