Significant mobility enhancement in extremely thin highly doped ZnO films

Abstract

Highly Ga-doped ZnO (GZO) films of thicknesses d = 5, 25, 50, and 300 nm, grown on 160-nm ZnO buffer layers by molecular beam epitaxy, had 294-K Hall-effect mobilities μH of 64.1, 43.4, 37.0, and 34.2 cm2/V-s, respectively. This extremely unusual ordering of μH vs d is explained by the existence of a very high-mobility Debye tail in the ZnO, arising from the large Fermi-level mismatch between the GZO and the ZnO. Scattering theory in conjunction with Poisson analysis predicts a Debye-tail mobility of 206 cm2/V-s at the interface (z = d), falling to 58 cm2/V-s at z = d + 2 nm. Excellent fits to μH vs d and sheet concentration ns vs d are obtained with no adjustable parameters.

Rapid synthesis of blue emitting ZnO nanoparticles for fluorescent applications

“…Synthesis and characterization of zinc oxide (ZnO) nanoparticles has found widespread interest during past few years due to their unique electro optical properties, which can be employed in devices such as ultraviolet (UV) light-emitting diodes (LEDs) and blue luminescent devices [13].…”

Structural and optical properties of individual Zn2GeO4 particles embedded in ZnO

“…Highly conductive ZnO films used as TCOs can be realized via doping by aluminum [3], and gallium [4][5][6][7], but also using group IV elements such as silicon and germanium (Ge) [8]. Ge is of particular interest, since embedded nanoparticles of elemental Ge and several of its oxide forms are semiconducting with a size-dependent tunability [9], while the unprecipitated Ge remains as donor on substitutional site in the ZnO matrix [10,11].…”

Direct observation of conduction band plasmons and the related Burstein-Moss shift in highly doped semiconductors: A STEM-EELS study of Ga-doped ZnO

“…On the other hand, highly doped semiconductors, including TCOs, have lower concentrations and are highly suitable for both telecom and PV applications [7][8][9][10]. One well-* cecilie.granerod@fys.uio.no established semiconductor material that can be doped heavily enough is ZnO, where Ga or Al are important dopants [11][12][13][14] that introduce minimal lattice distortions [15,16]. ZnO has a high conductivity and transparency due to a wide optical band gap (∼3.3 eV) and a high exciton binding energy (60 meV), where the optical and electronic properties can be tuned by doping.…”