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We report on growth and electrical properties of α-Ga2O3films prepared by halide vapor phase epitaxy (HVPE) at 500 °C on α-Cr2O3buffers predeposited on sapphire by magnetron sputtering. The α-Cr2O3buffers showed a wide microcathodoluminescence (MCL) peak near 350 nm corresponding to the α-Cr2O3bandgap and a sharp MCL line near 700 nm due to the Cr+intracenter transition. Ohmic contacts to Cr2O3were made with both Ti/Au or Ni, producing linear current–voltage ( I– V) characteristics over a wide temperature range with an activation energy of conductivity of ∼75 meV. The sign of thermoelectric power indicated p-type conductivity of the buffers. Sn-doped, 2- μm-thick α-Ga2O3films prepared on this buffer by HVPE showed donor ionization energies of 0.2–0.25 eV, while undoped films were resistive with the Fermi level pinned at ECof 0.3 eV. The I– V and capacitance–voltage ( C– V) characteristics of Ni Schottky diodes on Sn-doped samples using a Cr2O3buffer indicated the presence of two face-to-face junctions, one between n-Ga2O3and p-Cr2O3, the other due to the Ni Schottky diode with n-Ga2O3. The spectral dependence of the photocurrent measured on the structure showed the presence of three major deep traps with optical ionization thresholds near 1.3, 2, and 2.8 eV. Photoinduced current transient spectroscopy spectra of the structures were dominated by deep traps with an ionization energy of 0.95 eV. These experiments suggest another pathway to obtain p–n heterojunctions in the α-Ga2O3system.
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Using Highly Functional Cr 2 O 3 Interfacial Layer to Enhance the Electrical Performance of Au/InP Schottky Diodes
Abstract Herein, the significant impact of the spin‐coated Cr2O3interface layer on the electrical properties and performance characteristics of Au/undoped‐InP (Au/InP) Schottky diodes (SD) is reported. The material characterization of spin‐coated Cr2O3films using a wide variety of analytical techniques, namely, atomic force microscopy, field emission scanning electron microscope, X‐ray diffraction, Fourier transform infrared spectroscopy, and Raman spectroscopy, indicate the formation of hexagonal phase, nanocrystalline, and stoichiometric Cr2O3on InP. Optical absorption measurements reveal a bandgap of ≈3.5 eV. In‐depth analyses and detailed measurements of current‐voltage (I–V) and capacitance‐voltage (C‐V) employed to assess the interface characteristics and electrical performance of the Au/InP (SD) versus Au/Cr2O3/InP (MIS) devices. Compared to SD, MIS revealed superior rectifying properties. Indicating that the Cr2O3interface layer significantly influences the barrier height (ΦBH) of SD, the estimated ΦBH(0.64 eV (I–V)/0.86 eV (C‐V)) is higher than that of SD (0.57 eV (I–V)/0.67 eV (C‐V)). In addition, Cheungs and Nordes' methods are used to obtain the ΦBH, ideality factor (n), and series resistance (RS). The equivalent ΦBHvalues obtained from current–voltage, Cheungs, and Nordes methods demonstrate stability and dependability in addition to validating their superior characteristics of MIS devices. The interface state density (NSS) for MIS is lower than the SD's, indicating that the effectiveness of Cr2O3layer significantly reduces NSS. Analyses to probe the mechanism demonstrate that, in SD and MIS, the Schottky emission controls the higher bias area, while the Poole‐Frenkel emission dominates the reverse conduction mechanism at the lower bias region. The present work convincingly demonstrates the potential application of the Cr2O3interfacial layer in delivering the enhanced performance and contributes to the progression of electrical devices for emerging electronics and energy‐related applications.
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- Award ID(s):
- 1827745
- PAR ID:
- 10586832
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Electronic Materials
- Volume:
- 11
- Issue:
- 12
- ISSN:
- 2199-160X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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