Abstract We report on the growth of violet emitting p-type ZnO thin films, with phosphorous (P) and nitrogen (N) codoping, using pulsed laser deposition. XPS studies show that the phosphorous is substituted at Zn site, whereas nitrogen is substituted at oxygen site. Hall measurements confirmed the p-type nature in codoped ZnO thin films. I-V characteristics of the heterojunction formed by n-Si and P, N: ZnO showed rectifying nature. Strong violet emission in PL spectra is attributed to the formation of zinc vacancies. We propose a defect complex, (P Zn -V Zn -4N O ), which acts as an effective acceptor in the P and N codoped ZnO. © 2015 Elsevier B.V.

Nandita Dasgupta

Department of Electrical Engineering

Mamidanna Sri Ramachandra Rao

Department Of Physics

Hall effect

Heterojunctions

II-VI semiconductors

Metallic films

nitrogen

Optical films

Phosphorus

photoluminescence

Pulsed laser deposition

Pulsed lasers

Silicon compounds

Vacancies

X ray photoelectron spectroscopy

Zinc oxide

DEFECT COMPLEX

Hall measurements

IV characteristics

NITROGEN CODOPED

P type ZnO thin film

VIOLET EMISSION

ZINC VACANCY

Zn vacancies

Thin films

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Applied Surface Science

We report on the growth of ZnO nanostructures in different gas ambient (Ar and N 2 ) using pulsed laser deposition technique. Despite the similar growth temperature, use of N 2 ambient gas resulted in well-aligned nanorods with flat surface at the tip, whereas, nanorods grown with Ar ambient exhibited tapered tips. The Nanorods grown under N 2 ambient exhibited additional Raman modes corresponding to N induced zinc interstitials. The nanorods are c-axis oriented and highly epitaxial in nature. Photoluminescence spectroscopy reveals that the UV emission can be significantly enhanced by 10 times for the nanorods grown under Ar ambient. The enhanced UV emission is attributed to the reduction in polarization electric field along the c-axis. n-ZnO nanorods/p-Si heterojunction showed rectifying I–V characteristics with a turn of voltage of 3.4 V. © 2017 Elsevier B.V.

Enhanced photoluminescence and heterojunction characteristics of pulsed laser deposited ZnO nanostructures

Enhancing luminescence characteristics is one of the key challenges in ZnO nanostructures for highly efficient UV-blue LEDs and laser diodes. Non-conventional PLD growth parameters have been used to tailor the polar and semi-polar surfaces of ZnO nanostructures on MgO substrates. Despite the similar growth temperature, use of N2 ambient gas allowed the fabrication of well-aligned polar nanostructures; whereas, nanostructures grown with Ar ambient are semi-polar in nature. By means of cathodoluminescence spectroscopy, we demonstrate that the UV emission can be significantly enhanced by 11 times for semi-polar nanostructures. The enhanced luminescence is attributed to reduced polarization electric fields along the c-axis. © 2016 The Royal Society of Chemistry.

Fulltext

RSC Advances

Polarity control and enhanced luminescence characteristics of semi-polar ZnO nanostructures grown on non-polar MgO(100) substrates

Doping lithium (Li) and/or nitrogen (N) in ZnO and activation of shallow acceptors thereby have drawn specific scientific interest for the last few years. A comprehensive study employing Raman spectroscopy is being reported here on N and Li implantation effects in ZnO. Strong presence of 275 cm−1 Raman mode after N and (Li,N) implantation confirms its relation with doped nitrogen in ZnO. Weak presence of 510 cm−1 mode in the high fluence implanted ZnO indicates its origin with interstitial defects. No extra Raman mode has been identified in Li implanted samples. Raman mode with anomalously large intensity is found at 1562 cm−1 after (Li,N) co-implantation (highest fluence). Implantation causes huge increase of Raman modes ~ 540, 555 and 579 cm−1, with the last two bearing clear co-relations with interstitial Zn and O vacancy, respectively. To identify shallow acceptors due to dopant-defect complex, low temperature photoluminescence (PL) has been monitored but only donor related excitonic features are visible in the near band edge (NBE) emission. However, indications in favour of deep acceptors states are noted, particularly when Li is present in the sample. The deep acceptor level may be at~ 300 meV above the valence band consistent with previous results. © 2018 Elsevier Ltd

Materials Science in Semiconductor Processing

Raman spectroscopic analysis on Li, N and (Li,N) implanted ZnO

We report on the growth of Li-Ni codoped p-type ZnO thin films using pulsed laser deposition. Two mole percent Li monodoped ZnO film shows highly insulating behavior. However, a spectacular decrease in electrical resistivity, from 3.6 × 10 3 to 0.15 Ω cm, is observed by incorporating 2 mol % of Ni in the Lidoped ZnOfilm.Moreover, the activation energy drops to 6meV from78 meV with Ni incorporation in Li:ZnO lattice. The codoped [ZnO:(Li, Ni)] thin film shows p-type conduction with room temperature hole concentration of 3.2 × 10 17 cm -3. Photo-Hall measurements show that the Li-Ni codoped p-ZnOfilm is highly stable even with UV illumination. XPS measurements reveal that most favorable chemical state of Ni is Ni 3+ in (Li, Ni): ZnO. We argue that these Ni 3+ ions act as reactive donors and increase the Li solubility limit. Codoping of Li, with other transitional metal ions (Mn, Co, etc.) in place of Ni could be the key to realize hole-dominated conductivity in ZnO to envisage ZnO-based homoepitaxial devices. © 2011 American Chemical Society.

ACS Applied Materials and Interfaces

A codoping route to realize low resistive and stable p-type conduction in (Li,Ni):ZnOThin films grownby pulsed laserdeposition

Thin Solid Films

Photovoltaic property of n-ZnO/p-Si heterojunctions grown by pulsed laser deposition

Fabrication and characterization of P–N dual acceptor doped p-type ZnO thin films

Materials Science and Engineering: B

Deposition of Na–N dual acceptor doped p-type ZnO thin films and fabrication of p-ZnO:(Na, N)/n-ZnO:Eu homojunction

Journal of Applied Physics

Conversion mechanism of conductivity of phosphorus-doped ZnO films induced by post-annealing

Zn-vacancy induced violet emission in p-type phosphorus and nitrogen codoped ZnO thin films grown by pulsed laser deposition

Journal	Data powered by TypesetApplied Surface Science
Publisher	Data powered by TypesetElsevier B.V.
ISSN	01694332
Open Access	No