Besides its high stability, CsPbBr 3 possesses interesting electronic and optoelectronic properties such as high attenuation above the band gap, good photoresponse, large electron and hole mobility, long lifetimes, low excitation binding energy, halogen self-passivation, defect tolerance, luminosity, etc. [1,4-11] Device-quality single crystals have been prepared using a number of methods including a high-temperature process, [4] solution-based methods such as antisolvent vapor crystallization (AVC), [7,8,10] and inverse temperature crystallization. [12] The carrier concentration (holes) of these crystals varies in the range of 5 × 10 7 to 1 × 10 8 cm −3[9,10] and about 1 × 10 9 cm −3 for electrons, [9] resulting in nearly intrinsic crystals with resistivities in the range of 1-3 GΩ cm. [10] As a reference, Bridgmangrown crystals show resistivities as high as ≈340 GΩ cm [4,13] and mobility-lifetime (μτ) product for electrons and holes in the range of 1.7 × 10 −3 to 4.5 × 10 −4 cm 2 V −1 and 1.3 × 10 −3 to 9.5 × 10 −4 cm 2 V −1 , respectively. [4,14,15] These μτ values are better than that of CdZnTe (CZT) and CdTe. It is important to note that the electron μτ product of CZT and CdTe [4,11] is in the lower range of the corresponding values for CsPbBr 3 while the hole μτ product is only 0.1% that of CsPbBr 3. [4] The reported use of CsPbBr 3 for radiation sensing is limited to single crystals, except for its use as a thin film in X-ray scintillators. [1,3] There are no reports for direct radiation detection using thin-film diodes based on CsPbBr 3. This is related to the lack of deposition techniques for thick CsPbBr 3 films. The close space sublimation (CSS) process reported here addresses this problem. Although the intrinsic phase purity and crystal quality of single crystals offer improved optoelectronic properties, the high cost of the single crystal approach renders this option nonviable for portable and large-area applications, hence thin films are a better option. Furthermore, the photon attenuation coefficient of CsPbBr 3 is linear and comparable to that of CZT for energies up to 1000 keV, [4] but no exhaustive studies exist for the interaction of CsPbBr 3 with charged particles (α, β, etc.) or for higher photon energies such as gamma rays. The interaction of CsPbBr 3 2D nanosheets with ionizing radiation has been reported recently showing scintillation performance comparable to commercial crystals. [1] The observed The majority of solid-state radiation sensors are predominantly single crystals. However, for low-cost and large-area device applications, thin films are a better option. The first evidence of neutron detection using a Gallium Oxide/Cesium Lead Bromide (Ga 2 O 3 /CsPbBr 3) solid-state diode enabled by an innovative close space sublimation (CSS) method that allows deposition of thick CsPbBr 3 films is demonstrated. Furthermore, indirect neutron sensing is achieved using a 10 B layer for diodes biased at voltages as low as-5 V, showing the potential for low-power operation. The neutron response is ...

Perovskite-based semiconductors, such as methylammonium and cesium lead halides (MPbX3: M = CH3NH3 + or Cs+; X = I–, Br–, or Cl–), have attracted immense attention for several applications, including radiation detection, due to their excellent electronic and optical properties.1,2,3,4,5,6 In addition, the combination of perovskites with other materials enables unique device structures. For example, robust and reliable diodes result when combined with metal oxide semiconductors. This device can be used for detection of nonionizing and ionizing radiation. In this paper, we report a unique perovskite single-crystal-based neutron detector using a heterojunction diode based on single-crystal MAPbBr3 and gallium oxide (Ga2O3) thin film. The MAPbBr3/Ga2O3 diodes demonstrate a leakage current of ∼7 × 10–10 A/mm2, an on/off ratio of ∼102, an ideality factor of 1.41, and minimal hysteresis that enables alpha particle, gamma-ray, and neutron detection at a bias as low as (−5 V). Gamma discrimination is further improved by 85% by optimizing the thickness of the perovskite single crystal. The MAPbBr3/Ga2O3 diodes also demonstrate a neutron detection efficiency of ∼3.92% when combined with a 10B neutron conversion layer.

Low-temperature solution-processed inorganic–organic hybrid gate dielectrics are considered as emerging candidates for future low-cost flexible electronic devices, which are alternatives to high-temperature inorganic-based gate dielectric materials. In the present work, we developed a novel inorganic–organic HfO2–PMMA hybrid dielectric material by an efficient eco-friendly sol–gel method, deposited by spin-coating technique and converted into dielectric thin films at a very low thermal annealing temperature of 185 °C. The HfO2–PMMA hybrid thin-film formation was systematically investigated by FTIR and XPS techniques. Subsequently, a very low surface roughness of 0.8 nm and high uniformity of hybrid thin films were observed by tapping-mode AFM. Also, the thin films showed a hydrophilic nature with a high surface energy of 59.9 mJ/m2 as observed by the contact angle technique. The insulating properties of this hybrid film, studied by C–V and I–V measurements, showed very low leakage current density under 1 nA/cm2 at −5 V, high gate capacitance of 106 nF/cm2, and high dielectric constant of 11.3 at 1 kHz. With such dielectric properties, the hybrid thin films were tried as dielectric gate layers in room-temperature-sputtered ZnO thin-film transistors (TFTs). As-fabricated devices achieved low operating voltage, less than 5 V, with high saturation field effect mobility of 15.5 cm2 V–1 s–1, very low threshold voltage of 0.5 V, high on/off current ratio of 106, and low subthreshold slope of 0.37 V/dec. These results reveal the promising application of the HfO2–PMMA hybrid material as the gate dielectric for the fabrication of ZnO-based TFTs at low temperature.

This paper reports a simple and novel conformal doping strategy for microstructured silicon diodes using enriched 10 B for sidewall doping while enabling enhanced neutron sensitivity. Monte-Carlo nuclear particle (MCNP) code simulations were initially used to calculate the neutron detection efficiency in the microstructured diodes as a function of geometry and pitch. A high-temperature anneal in 10 B-filled diodes results in a conformal silicon p + layer along the side walls of the trenches in the diodes. This results in large neutron detection areas and enhanced neutron detection efficiency when compared with planar detectors. With the method discussed here, a thermal neutron detection of ∼21% efficiency is achieved, which is significantly higher than the efficiency achieved in planar detectors (∼3.5%). The higher efficiency is enabled by the 10 B acting as a source for conformal doping in the trenches, resulting in lower leakage current while also enabling neutron sensitivity in the microstructured diodes.

No abstract