Herein the fabrication and practical applications of p-MgSe thin films as active p-layer of electronic devices are reported. MgSe films are prepared by a vacuum evaporation technique onto n-Si substrates under a vacuum pressure of 10-5 mbar. The films are morphologically, structurally, electrically and opto-electronically investigated. Having identified the work function of p-MgSe as 6.74 eV, the role of Ag, C, Au and Pt metal contacts on the performance of the n-Si/p-MgSe (SM) diodes are studied. It is observed that high rectification ratios of ~104 and 102 are achieved at an applied voltage of 3.0 V for the Ag/SM/C and Ag/SM/Ag diode structures, respectively. In addition, a current responsivity to visible and infrared light of ~0.70 A/W is observed for the Ag/SM/Ag channels. The noise equivalent ratios, the external quantum efficiency and the detectivity of the Ag/SM/Ag diodes suit requirements of visible light and infrared communication detectors. Moreover, studies of the capacitance-voltage characteristics showed capacitor characteristics. The depleting of the Ag/SM/Ag capacitors is possible up to 50 MHz. Furthermore, analyzing the capacitance, resistance and cutoff frequency spectra have shown that the Ag/SM/Ag device channels can perform as negative resistance sources with cutoff frequency values that suits 6G technology requirements

Herein a new class of MgSe gigahertz/terahertz band filters operatives in the frequency domain of 1.0 GHz-1.86 THz is fabricated and experimentally tested. MgSe band filters are coated onto glass and indium tin oxide (ITO) substrates by the thermal evaporation technique under a vacuum pressure of 10-5 mbar. Thin films of MgSe are structurally, morphologically, compositionally, optically and electrically characterized. It is observed that ITO substrates induce the growth of monophasic of MgSe, enhances the crystallinity of the films and blueshifts the energy band gaps of MgSe. Practical applications were verified by impedance spectroscopy technique through imposing an ac signal of driving frequency in the domain of 10.0 MHz-1.8 GHz between the terminals of ITO/MgSe/Au (IMA) devices. It is observed that the IMA devices exhibit negative capacitance effect. Analysis of the cutoff frequency spectra has shown that IMA devices can reveal wide range of tunability in the gigahertz frequency domain. In addition, the cutoff frequency spectra show values reaching ~1.86 THz for signals of driving frequencies of ~1.0 GHz. Evaluation of the magnitude of the reflection coefficient spectra and return loss spectra for these devices show that the IMA devices can perform as bandstop filters with return loss values exceeding 20 dB at 1.0 GHz. The features of the ITO/MgSe/Au devices are appropriate for the 5G/6G technology needs indicating that the device can be employed in communication technology and other gigahertz/terahertz applications.

Creatinine measurement in blood and urine is an important diagnostic test for assessing kidney health. In this study, a molecularly imprinted polymer was obtained by incorporating fluorescent nanodiamond into a creatinine-imprinted polyacrylamide hydrogel. The quenching of peak nanodiamond fluorescence was significantly higher in the creatinine-imprinted polymer compared to the non-imprinted polymer, indicative of higher creatinine affinity in the imprinted polymer. Fourier transform infrared spectroscopy and microscopic imaging was used to investigate the nature of chemical bonding and distribution of nanodiamonds inside the hydrogel network. Nanodiamonds bind strongly to the hydrogel network, but as aggregates with average particle diameter of 3.4 ± 1.8 µm and 3.1 ± 1.9 µm for the non-imprinted and molecularly imprinted polymer, respectively. Nanodiamond fluorescence from nitrogen-vacancy color centers (NV− and NV0) was also used to detect creatinine based on nanodiamond-creatinine surface charge interaction. Results show a 15% decrease of NV−/NV0 emission ratio for the creatinine-imprinted polymer compared to the non-imprinted polymer, and are explained in terms of changes in the near-surface band structure of diamond with addition of creatinine. With further improvement of sensor design to better disperse nanodiamond within the hydrogel, fluorescent sensing from nitrogen-vacancy centers is expected to yield higher sensitivity with a longer range (Coulombic) interaction to imprinted sites than that for a sensor based on acceptor/donor resonance energy transfer.

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