Electrical and Photoresponse Properties of an Intramolecular p-n Homojunction in Single Phosphorus-Doped ZnO Nanowires

Abstract

The single-crystal n-type and p-type ZnO nanowires (NWs) were synthesized via a chemical vapor deposition method, where phosphorus pentoxide was used as the dopant source. The electrical and photoluminescence studies reveal that phosphorus-doped ZnO NWs (ZnO:P NWs) can be changed from n-type to p-type with increasing P concentration. Furthermore, we report for the first time the formation of an intramolecular p-n homojunction in a single ZnO:P NW. The p-n junction diode has a high on/off current ratio of 2.5 x 10(3) and a low forward turn-on voltage of approximately 1.37 V. Finally, the photoresponse properties of the diode were investigated under UV (325 nm) excitation in air at room temperature. The high photocurrent/dark current ratio (3.2 x 10(4)) reveals that the diode has a potential as extreme sensitive UV photodetectors.

A Perspective on Nanowire Photodetectors: Current Status, Future Challenges, and Opportunities

“…Liu et al [276] reported a series of measurements on a ZnO-NW-based FET device, which has response to visible light under different environments (air, vacuum, N 2 , and O 2 ). ZnO:P NWs can play an important and significant role in optoelectronics, since these NWs can be changed from n-type to p-type with an increase in phosphorus concentration [277]. If a feasible and rapid process is developed to dope ZnO NWs with higher concentration, it would rapidly change the way that ZnO NW PDs are deployed in complex systems.…”

High-Performance Ultraviolet Photodetector Based on Graphene Quantum Dots Decorated ZnO Nanorods/GaN Film Isotype Heterojunctions

“…Fabrication of one-dimensional ZnO is found to be an efficient solution to improve its photodetection and photoresponse performance. Meanwhile, various nanostructures including heterostructures [16], homojunctions [17], nanocomposites [18, 19], and ZnO of special morphologies [20] have also been sequentially reported which could furtherly shorten the rise and decay time of ZnO-based UV detectors. By comparison, n-ZnO/n-GaN isotype heterojunctions have been proven to be a superior choice owing to their similar crystal structure, lattice parameter, and wide band gaps (3.37 eV for ZnO and 3.39 eV for GaN), which could generate carriers from the interior localized states excited by light or electric field.…”

Fabrication and characterization of single ZnO microwire Schottky light emitting diodes

“…To fabricate high quality ZnO micro/nanostructure devices, the growth of reproducible and high quality p-type ZnO is very important. However, there have many reasons make p-type acceptor doping of ZnO very difficult, including low solubility of acceptor dopants, self-compensation, deep level of impurities and structural instability [7][8][9]. So, in order to realize ZnO optoelectronic device, an alternative approach is fabrication of heterojunctions and Schottky contacts on n-ZnO micro/nanostructures [10].…”