Current helium-3 tube based thermal neutron detectors have shortcomings in achieving simultaneously high efficiency and low voltage while maintaining adequate fieldability performance. By using a three-dimensional silicon p-i-n diode pillar array filled with boron-10 these constraints can be overcome. The fabricated pillar structured detector reported here is composed of 2μm diameter silicon pillars with a 4μm pitch and height of 12μm. A thermal neutron detection efficiency of 7.3+∕−0.6% and a neutron-to-gamma discrimination of 105 at 2V reverse bias were measured for this detector. When scaled to larger aspect ratio, a high efficiency device is possible.

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Articles you may be interested inThermal neutron detection using a silicon pad detector and 6LiF removable converters Rev. Sci. Instrum. 84, 033503 (2013); 10.1063/1.4794768Self-powered micro-structured solid state neutron detector with very low leakage current and high efficiency Development of a thermal neutron detector based on scintillating fibers and silicon photomultipliers Rev. Sci. Instrum. 81, 093503 (2010); 10.1063/1.3480995 6:1 aspect ratio silicon pillar based thermal neutron detector filled with B 10

We report deep-submicrometer gate-recessed and field-plated AlGaN-GaN HEMTs and their state-of-the-art continuous wave (CW) power performance measured at 30 GHz. The AlGaN-GaN HEMTs exhibit a CW power density of 5.7 W/mm with a power-added efficiency (PAE) of 45% and drain-efficiency of 58% at ds = 20 V. At ds = 28 V, the output power density is measured as high as 6.9 W/mm with both PAE and output power increasing with input power level. Compared to conventional T-gated AlGaN-GaN HEMTs, the output power density and PAE of gate-recessed AlGaN-GaN HFETs are improved greatly, along with the excellent pulsed IVs. We attribute the improvement to both a field-plating effect and a vertical separation of the gate plane from surface states.Index Terms-Field-effect transistor (FET), GaN, HEMT, millimeter-wave (mmWave).