Demonstration of a High Open-Circuit Voltage GaN Betavoltaic Microbattery

Abstract

A high open-circuit voltage betavoltaic microbattery based on a GaN p-i-n diode is demonstrated. Under the irradiation of a 4×4 mm 2 planar solid 63 Ni source with an activity of 2 mCi, the open-circuit voltage Voc of the fabricated single 2×2 mm 2 cell reaches as high as 1.62 V, the short-circuit current density Jsc is measured to be 16nA/cm 2 . The microbattery has a fill factor of 55%, and the energy conversion efficiency of beta radiation into electricity reaches to 1.13%. The results suggest that GaN is a highly promising potential candidate for long-life betavoltaic microbatteries used as power supplies for microelectromechanical system devices.

Modeling, design, fabrication and experimentation of a GaN-based,63Ni betavoltaic battery

“…Previous studies on the conversion of 63 Ni beta particle energy into electricity by means of GaN-based p-n junctions reported output powers from 23 pW to 0.57 nW [2][3][4][5]. Note that, in practice, the power output is typically lower than theor etical expectations, which are often above 2 nW [6].…”

Review of using gallium nitride for ionizing radiation detection

“…[25][26][27] In one of their p-i-n devices, using a 63 Ni source with activity of 2 mCi, an open-circuit voltage of 1.62 V, short-circuit current density of 16 nA/cm 2 , filling factor of 55%, and energy conversion efficiency of 1.13% were obtained. 26 Another group lead by Lu studied both Schottky and p-i-n structures, 23,28,29 reporting a p-i-n device with an open circuit voltage of 1.07 V, short circuit current of 0.554 nA, and a filling factor of 24.7% using a 147 Pm source. 23 The performance of GaN-based beta-voltaic devices is still far from its theoretical calculated values, and further improvement largely relies on the availability of high quality, thick GaN.…”

“…For X-ray detectors, Schottky Metal-Semiconductor-Metal (MSM), 15 Schottky diode, 16,17 and p-i-n structures 22 have all been reported. For electron detection, the applications for making betavoltaic energy converters, 23,24 using pn, 25 p-i-n, 23,[26][27][28] and Schottky type 29 structures have now been tested. Thermal neutron detection using a 6 Li converter in a sandwich structure has been recently reported.…”

A high open-circuit voltage gallium nitride betavoltaic microbattery

“…As a beta irradiation of 0.5 mCi 63 Ni is illuminating the effective area of the microbattery, the direct beta-electron current (I Ni-63 ) is only 2.96 pA, in comparison with short-circuit current of 568 pA caused by beta energy conversion, the current multiplication factor is 192 by calculating I sc /I Ni-63 , thus higher current output can be expected when illuminate the microbattery with higher activity of 63 Ni source. In our previous battery devices [21], we used a HR i-GaN layer with width of 1200 nm, the measured I sc reached to 640 pA under the same 63 Ni source irradiation, which indicate that the width of GaN layer as energy absorbed region has a significant influence.…”