A high open-circuit voltage betavoltaic microbattery based on a gallium nitride (GaN) p–i–n homojunction is demonstrated. As a beta-absorbing layer, the low electron concentration of the n-type GaN layer is achieved by the process of Fe compensation doping. Under the irradiation of a planar solid 63Ni source with activity of 0.5 mCi, the open-circuit voltage of the fabricated microbattery with 2 × 2 mm2 area reaches as much as 1.64 V, which is the record value reported for betavoltaic batteries with 63Ni source, the short-circuit current was measured as 568 pA and the conversion effective of 0.98% was obtained. The experimental results suggest that GaN is a high-potential candidate for developing the betavoltaic microbattery.

This paper presents a passive wireless polymer-derived silicon carbonitride (SiCN) ceramic sensor based on cavity radio frequency resonator together with integrated slot antenna. The effect of the cavity sensor dimensions on the Q-factor and resonant frequency is investigated by numerical simulation. A sensor with optimal dimensions is designed and fabricated. It is demonstrated that the sensor signal can be wirelessly detected at distances up to 20 mm. Given the high-temperature stability of the SiCN, the sensor is very promising for high-temperature wireless sensing applications. V

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We report a novel betavoltaic device with significant conversion efficiency by using electrochemically reduced graphene oxide (ERGO) on TiO2 nanotube arrays (TNTAs) for enhancing the absorption of beta radiation as well as the transportation of carriers. ERGO on TNTAs (G-TNTAs) were prepared by electrochemical anodization and subsequently cyclic voltammetry techniques. A 10 mCi of (63)Ni/Ni source was assembled to G-TNTAs to form the sandwich-type betavoltaic devices (Ni/(63)Ni/G-TNTAs/Ti). By I-V measurements, the optimum betavoltaic device exhibits a significant effective energy conversion efficiency of 26.55% with an open-circuit voltage of 2.38 V and a short-circuit current of 14.69 nAcm(-2). The experimental results indicate that G-TNTAs are a high-potential nanocomposite for developing betavoltaic batteries.