Epitaxial GaN Thin Films Prepared by Polymer-Assisted Deposition

Abstract

Epitaxial GaN thin films have been deposited on (0001) sapphire substrates by a chemical solution approach of polymer-assisted deposition. The films are smooth with no detectable cracks or pores, as observed by scanning electron microscopy and atomic force microscopy. Microstructural studies by X-ray diffraction and transmission electron microscopy show that the GaN films have a hexagonal structure with an epitaxial relationship between the film and the substrate of (0001)GaN||(0001)Al2O3 and [112̅0]GaN||[101̅0]Al2O3 . The films with a room temperature resistivity of around 0.13 Ω·cm exhibit photoluminescence characteristic of wurtzite hexagonal GaN.

A Review of Epitaxial Metal-Nitride Films by Polymer-Assisted Deposition

“…The PAD grown GaN film is conductive with a room temperature resistivity of around 0.13 Ω•cm. The room temperature Hall measurement indicates its n-type conductivity with a carrier concentration of 2.1 × 10 20 cm -3 and an electron mobility of 2 cm 2 V -1 S -1 [51]. The carrier mobility is still relatively low.…”

“…The electrical resistivity ( ρ ) was measured from 5-300 K using a standard four-probe technique by a Quantum Design Physical Properties Measurement System (PPMS). Figure 1 shows the XRD θ -2θ scan, rocking curve, and φ -scans of a GaN film on sapphire substrate annealed in ammonia gas at 900°C [51]. Only (0002) peak from hexagonal GaN is observed, indicating that the film is preferentially oriented along the c-axis perpendicular to the substrate surface.…”

“…Recently, we have extended this technique to prepare epitaxial nitride films. For example, hexagonal GaN [51], superconducting cubic NbN [52] [55] have been successfully prepared by PAD. In this review, we will summarize the nitrides prepared by PAD as shown in Table 1.…”

“…X-ray diffraction patterns: (a) θ -2θ scan of GaN film on sapphire. Inset shows the rocking curve of (0002) reflection; (b) φ -scans from (10 12) reflection of GaN and(10 14) reflection of sapphire (Ref [51]…”

Multiferroic BaTiO3-CoFe2O4 Nano Composite Thin Films Grown by Polymer-Assisted Deposition

“…Recently, the Polymer-Assisted Deposition (PAD), a chemical solution based deposition technique, has been reported to grow the epitaxial nanocomposite films successfully [19]. PAD has its own advantages such as low cost, easy setup, and large areas coating, and it has been reported to be a feasible approach to produce high-quality epitaxial metal-oxide and nitrides films [20][21][22][23][24][25]. As a recently developed deposition technique, the research on the growth mechanism of PAD is still under way.…”