The metastable p-type oxide SnO: application aspects and its pn-heterojunction with beta-Ga2O3

Tin monoxide (SnO) is one of the few p-type semiconducting oxides with reasonably high hole mobility (>1cm^2/Vs). It possesses a challenging metastability with respect to Sn and the n-type semiconducting oxide SnO2, which is adressed in this talk by a phase diagram, presenting a rapid in-situ approach to find the growth window for SnO during plasma-assisted molecular beam epitaxy, and by time and temperature stability investigations of the grown SnO layers. The nondegenerate hole transport properties of the obtained, (001)-oriented single crystalline layers are shown and discussed. As an application example SnO/beta-Ga2O3 vertical pn heterojunction diodes were prepared. Their high rectification (2x10^8 at +/-1V) allows for pn junction isolation of p-type SnO devices on top of n-type Ga2O3 substrates. The diodes exhibited an ideality factor of ~1.2, a built-in voltage of 0.96V, and an estimated peak breakdown electric field of 2.2 MV/cm in the Ga2O3.