p-Type conductivity of hexagonal boron nitride as a dielectrically tunable monolayer: modulation doping with magnesium

Abstract

Hexagonal boron nitride (h-BN) is the widest band gap 2D material (>6 eV), which has attracted extensive attention. For exploring potential applications in optoelectronic devices, electrical conductivity modulation (n or p type) is of extreme importance. Here, we report the achievement of a large-scale and high quality h-BN monolayer with p-type conductivity by modulation doping of Mg using a low pressure chemical vapor deposition method. A large-scale monolayer h-BN (>10 inches) was grown by using a wound Cu foil roll on a multi-prong quartz fork. Magnesium nitride is used as a dopant precursor in a separate line due to its appropriate melting point and decomposition temperature. Density functional theory calculations revealed that the acceptor level introduced by Mg is almost pinned into the valence band and the activated holes are highly delocalized into the surrounding h-BN lattices. The h-BN:Mg monolayer showed a p-type conductivity with a considerable surface current of over 12 μA and a hole density of 1.7 × 10 cm. The dielectrically tunable h-BN monolayer makes the fabrication of advanced 2D optoelectronic devices in short wavelength possible.

Towards P-Type Conduction in Hexagonal Boron Nitride: Doping Study and Electrical Measurements Analysis of hBN/AlGaN Heterojunctions

“…At room temperature, the resistivity of the sample with the highest doping (D) was 2 × 10 4 Ω•cm, with a doping concentration of 5 × 10 15 cm −3 . These values can be compared to those obtained by Sun et al [20] who reported a resistivity and doping concentration of 1.2 × 10 −5 Ω•cm and of 1.7 × 10 14 cm −2 , respectively, for an h-BN monolayer grown on Cu foil and transferred on SiO 2 . For a thicker layer of h-BN (300 nm), the reported resistivity and doping concentration are 2.3 Ω•cm and 1.1 × 10 18 cm −3 [7,8], respectively.…”

“…Furthermore, when compared to the peak position of sample A (25.86 • ), a shift of the (002) peak was observed in sample B (25.72 • ). This may be related to the deformation of the surrounding lattice because of the difference of atom sizes between B and Mg [20]. However, the peak shift at the lower angle was not observed in samples C and D. This is related to the formation of an accumulation of disordered phases in samples C and D, which overcomes the effect of Mg incorporation.…”

“…Previously, it was reported that the p doping of h-BN can be achieved using Zn, Be and Mg as dopants [13][14][15][16][17][18][19][20]. More recently, contradicting experimental and theoretical studies of p-type conductivity of h-BN have been published.…”

Optoelectronic Properties of Monolayer Hexagonal Boron Nitride on Different Substrates Measured by Terahertz Time-Domain Spectroscopy

“…It is known that the high quality free-standing ML hBN is normally weakly conducting [14]. Similar to conventional semiconductor based devices, ML hBN based electronic and optoelectronic devices are often placed on the substrate.…”

Highly Deep Ultraviolet–Transparent h-BN Film Deposited on an Al0.7Ga0.3N Template by Low-Temperature Radio-Frequency Sputtering

“…These properties mean that h-BN is a promising candidate material for use as a p-type layer in optical devices. There have been a number of reports of h-BN layer synthesis using chemical vapor deposition (CVD) methods [16][17][18][19]. In these studies, the favored substrate materials are mostly metals such as Ni, Cu, or Fe, which are used as catalytic layers to promote h-BN film formation.…”