A single-walled carbon nanotubes betavoltaic microcell

This paper reports a new type betavoltaic (BV) microcell based on intrinsic p-type semiconductive single-walled carbon nanotubes (s-SWNTs). Our device composes of Au and Ti asymmetrical electrode pairs with s-SWNTs laid over them forming Schottky junction with Ti and ohmic contact with Au. SWNT bundles were self-assembled between Au and Ti electrodes by Dieletrophoretic (DEP) technique, and metallic SWNTs (m-SWNTs) were selectively eliminated by current-induced electrical breakdown method. 3.3mCi/cm² thin-film ⁶³Ni serves as β particles source, with 100-year half-time and low toxicity. Test results show that SWNTs BV microcell has the open circuit voltage (V_OC) of 26mV, short circuit current density (J_SC) of 2.19μA/cm² and energy conversion efficiency (η) of 4.44%.