Chemical manipulation of hydrogen induced high p-type and n-type conductivity in Ga2O3

Abstract

Advancement of optoelectronic and high-power devices is tied to the development of wide band gap materials with excellent transport properties. However, bipolar doping (n-type and p-type doping) and realizing high carrier density while maintaining good mobility have been big challenges in wide band gap materials. Here P-type and n-type conductivity was introduced in β-Ga2O3, an ultra-wide band gap oxide, by controlling hydrogen incorporation in the lattice without further doping. Hydrogen induced a 9-order of magnitude increase of n-type conductivity with donor ionization energy of 20 meV and resistivity of 10 -4 Ω.cm. The conductivity was switched to p-type with acceptor ionization energy of 42 meV by altering hydrogen incorporation in the lattice. Density functional theory calculations were used to examine hydrogen location in the Ga2O3 lattice and identified a new donor type as the source of this remarkable n-type conductivity. Positron annihilation spectroscopy confirmed this finding and the interpretation of the results. This work illustrates a new approach that allows a tunable and reversible way of modifying the conductivity of semiconductors and it is expected to have profound implications on semiconductor field. At the same time it demonstrates for the first time p-type and remarkable n-type conductivity in Ga2O3 which should usher in the development of Ga2O3 devices and advance optoelectronics and high-power devices.

Localized UV emitters on the surface of β-Ga2O3

“…What is the identity of these bright, localized emitters? Prior work has shown that hydrogen diffuses into Ga 2 O 3 and increases its conductivity 35 . Annealing in a reducing atmosphere such as hydrogen also decomposes the surface and may result in Ga-rich pits.…”

Split Ga vacancies and the unusually strong anisotropy of positron annihilation spectra in β−Ga2O3

“…Thanks to these properties, positron annihilation methods have been successful in identifying the role of native point defects in the electrical compensation of n-type doped compound semiconductors such as GaN, ZnO, AlN, InN, and In 2 O 3 [12][13][14][15][16], as well as their alloys such as InGaN and AlGaN [17][18][19][20][21][22]. In spite of the otherwise significant research interest in β-Ga 2 O 3 , the number of reported studies with positron annihilation is surprisingly low [23][24][25][26]. These studies suggest that cation vacancies contribute to the compensation of n-type conductivity, but also point out a potential difficulty in interpreting the positron annihilation signals.…”

Anisotropic and trap-limited diffusion of hydrogen/deuterium in monoclinic gallium oxide single crystals

“…Comparison of this value with the values listed in TableI suggest that V ib Ga 2H and V Ga(2) H-V O(2), which are the lowest energy configurations for V Ga 2H and V Ga H−V O -type defects, respectively, are excellent candidates for the filled trap. The E b 's of V ib Ga 3H and V ib Ga 4H, which were recently shown 57 to be more likely than the corresponding structures consisting of unshifted V Ga(1) ,31 are considerably lower than our experimental E b , and are 10 This is the author's peer reviewed, accepted manuscript. However, the online version of record will be different from this version once it has been copyedited and typeset.…”