Surface Charge Transfer Doping via Transition Metal Oxides for Efficient p-Type Doping of II–VI Nanostructures

Abstract

Wide band gap II-VI nanostructures are important building blocks for new-generation electronic and optoelectronic devices. However, the difficulty of realizing p-type conductivity in these materials via conventional doping methods has severely handicapped the fabrication of p-n homojunctions and complementary circuits, which are the fundamental components for high-performance devices. Herein, by using first-principles density functional theory calculations, we demonstrated a simple yet efficient way to achieve controlled p-type doping on II-VI nanostructures via surface charge transfer doping (SCTD) using high work function transition metal oxides such as MoO, WO, CrO, and VO as dopants. Our calculations revealed that these oxides were capable of drawing electrons from II-VI nanostructures, leading to accumulation of positive charges (holes injection) in the II-VI nanostructures. As a result, Fermi levels of the II-VI nanostructures were shifted toward the valence band regions after surface modifications, along with the large enhancement of work functions. In situ ultraviolet photoelectron spectroscopy and X-ray photoelectron spectroscopy characterizations verified the significant interfacial charge transfer between II-VI nanostructures and surface dopants. Both theoretical calculations and electrical transfer measurements on the II-VI nanostructure-based field-effect transistors clearly showed the p-type conductivity of the nanostructures after surface modifications. Strikingly, II-VI nanowires could undergo semiconductor-to-metal transition by further increasing the SCTD level. SCTD offers the possibility to create a variety of electronic and optoelectronic devices from the II-VI nanostructures via realization of complementary doping.

Enhanced transport in transistor by tuning transition-metal oxide electronic states interfaced with diamond

“…Note here that the main mechanism responsible for the Mo–OH formation in H y MoO 3− x is associated with the fact that hydrogen atoms from the H 2 O precursor form covalent bonds with the terminal oxygen and bridging atoms of MoO x (see atomic sketch in Fig. 1 ) ( 21 , 22 ). The coexistence of a low fraction of Mo 5+ and Mo 4+ reduction states further supports the oxide reduction characteristics of hydrogen-incorporated MoO 3 , forming the final H y MoO 3− x ( 20 ).…”

The improvement of photocatalytic activity of monolayer g-C3N4viasurface charge transfer doping

“…Carrier concentration and even conduction type of the semiconductor nanostructures can be readily tuned by varying the types as well as densities of surface dopants, leading to effective p-and n-type doping on the nanostructures. [33][34][35] SCTD has been proven to be a simple, nondestructive, and effective method to tune both the electronic and optical properties of low-dimensional semiconductors, [36][37][38][39][40][41][42][43][44] which is of fundamental importance to enable their wide applications in optoelectronic and electronic devices. For example, the electronic properties and carrier density of monolayer MoS 2 monolayer could be effectively modulated with electron acceptor, tetracyanoquinodimethane (TCNQ), and electron donor, tetrathiafulvalene (TTF).…”

Surface charge doping induced carrier type reversal in spin coated CdS/rGO layered nanohybrid films

“…Due to enhanced electron-phonon scattering, the electron mobility decreases while the holes concentration and mobility increases with rGO. Ultimately, the polarity of CdS can be tuned into p-type by surface charge transfer doping [6]. The role of SO mode and surface change doping with rGO incorporation in CdS are discussed in section 3.3.…”

“…Most of them exhibit Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. unipolar electrical conductivity, that is, n-type conductivity for ZnS, ZnSe, CdS, and CdSe and p-type conductivity for ZnTe and CdTe [6]. Among these, cadmium sulfide (CdS) is n-type semiconductor with direct band gap (2.42 eV) have promising candidate for efficient light harvesting media and excellent charge separation properties for their applications in photocatalytic degradation, sensor, bio imaging, solar cell, water splitting, photochemical catalysts and luminescence devices etc [7,8].…”