In this work, we investigate the optimal thickness of a semiconductor diode for thin-film solid state thermal neutron detectors. We evaluate several diode materials, Si, CdTe, GaAs, C (diamond), and ZnO, and two neutron converter materials, 10B and 6LiF. Investigating a coplanar diode/converter geometry, we determine the minimum semiconductor thickness needed to achieve maximum neutron detection efficiency. By keeping the semiconductor thickness to a minimum, gamma rejection is kept as high as possible. In this way, we optimize detector performance for different thin-film semiconductor materials.

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In this letter, we present the dc characteristics, stability, and low-frequency noise (LFN) measurements, for n-type indium arsenide nanowire (NW) parallel-array thin-film transistors (TFTs) with a global back gate. These devices perform with mobilities ranging from 200-1200 cm 2 V −1 s −1 and produce a threshold voltage shift less than 0.25 V after 10 000 s of stress. The resulting LFN measurements indicate that the 1/ f noise can be modeled by the number fluctuation model, at low drain currents, which can provide an essential guideline for the device design considerations of NW TFTs.

Thin film semiconductor neutron detectors are an attractive candidate to replace 3 He neutron detectors, due to the possibility of low cost manufacturing and the potential for large areas. Polycrystalline CdTe is found to be an excellent material for thin film charged particle detectorsan integral component of a thin film neutron detector. The devices presented here are characterized in terms of their response to alpha and gamma radiation. Individual alpha particles are detected with an intrinsic efficiency of >80%, while the devices are largely insensitive to gamma rays, which is desirable so that the detector does not give false positive counts from gamma rays. The capacitance-voltage behavior of the devices is studied and correlated to the response due to alpha radiation. When coupled with a boron-based neutron converting material, the CdTe detectors are capable of detecting thermal neutrons. V C 2014 AIP Publishing LLC.

A multi-stage thin film transistor (TFT)-based active pixel sensor (APS), capable of successfully detecting small impulses of charge resulting from incident alpha particle strikes, is presented. Detection of alpha particles is important in the field of neutron detection, where fully integrated thin-film-based detectors are an attractive alternative to conventional 3 He-based proportional counters owing to their low-cost and large-area scaling capability, combined with the use of readily available materials. A typical TFT process, however, produces only N-type devices with low electron mobilitiesmaking high-gain CMOS amplifier designs unfeasible. The disadvantages of using a TFT-only APS design are mitigated by cascading multiple low-gain TFT amplifiers, which results in a higher overall pixel gainsubsequently allowing for the successful detection and readout of alpha particle strikes. Presented is a new APS fabricated in an indium gallium zinc oxide TFT process is presented, and successful initial alpha response measurements are reported.