Photoluminescence and Electrical Properties of n-Ce-Doped ZnO Nanoleaf/p-Diamond Heterojunction

At a Glance

Metadata	Details
Publication Date	2022-10-26
Journal	Nanomaterials
Authors	Qinglin Wang, Yu Yao, Xianhe Sang, Liangrui Zou, Shunhao Ge
Institutions	Liaocheng University, Ludong University
Citations	8
Analysis	Full AI Review Included

Technical Documentation & Analysis: n-Ce-Doped ZnO Nanoleaf/p-Diamond Heterojunction

This documentation analyzes the research concerning the fabrication and characterization of n-Ce:ZnO NL/p-BDD heterojunctions, highlighting the critical role of high-quality Boron-Doped Diamond (BDD) films and connecting the material requirements directly to 6CCVD’s advanced MPCVD diamond capabilities.

Executive Summary

The research successfully demonstrates a high-performance n-Ce:ZnO NL/p-BDD heterojunction suitable for optoelectronic applications in harsh, high-temperature environments.

Enhanced Optoelectronics: Ce doping significantly enhances photoluminescence (PL) intensity and induces a pronounced blue shift of the UV emission peak (from 385 nm to 365 nm).
High Thermal Stability: The fabricated heterojunction devices maintain excellent rectification characteristics and electrical performance up to 175 °C.
Improved Electrical Performance: The turn-on voltage decreases favorably with increasing temperature (from 0.6 V at 25 °C to 0.4 V at 175 °C), demonstrating suitability for high-temperature operation.
Material Foundation: The device relies on a high-quality p-type Boron-Doped Diamond (BDD) film, prepared via Hot Filament Chemical Vapor Deposition (HFVVD).
Carrier Transport Insight: Detailed analysis confirms that at high temperatures, carrier transport shifts from tunneling-dominated (at RT) to natural diffusion and excess current states, leading to improved rectification.
Application Potential: The results confirm BDD’s potential for next-generation light-emitting devices operating in the dark blue region and under extreme conditions.

Technical Specifications

The following hard data points were extracted from the analysis of the p-type BDD material and the resulting heterojunction device performance.

Parameter	Value	Unit	Context
BDD Film Thickness	~4	µm	Prepared via HFVVD
BDD Carrier Mobility	38.9	cm² V^-1 s^-1	Measured via Hall effect
BDD Resistivity	1.09 x 10^-1	Ω cm	Measured via Hall effect
BDD Carrier Concentration	1.46 x 10¹⁸	cm^-3	Measured via Hall effect
Operating Temperature (Max)	175	°C	Demonstrated high-temperature stability
Turn-On Voltage (25 °C)	0.6	V	Standard operating condition
Turn-On Voltage (175 °C)	0.4	V	Improved performance at high temperature
UV Emission Peak (Undoped)	385	nm	n-ZnO/p-BDD heterojunction
UV Emission Peak (Ce-Doped)	365	nm	n-Ce:ZnO NL/p-BDD heterojunction (Blue Shift)
Rectification Ratio (175 °C)	29.37	Ratio	Measured at ±8 V bias
Ideal Factor (n) (175 °C)	4.61	Dimensionless	Decreases with temperature, indicating defect filling

Key Methodologies

The fabrication of the high-performance n-Ce:ZnO NL/p-BDD heterojunction involved precise material synthesis steps:

BDD Substrate Preparation: p-type BDD films (approximately 4 µm thick) were grown using Hot Filament Chemical Vapor Deposition (HFVVD).
Seed Layer Deposition: A thin ZnO seed crystal layer (~20 nm) was deposited onto the BDD films using magnetron sputtering.
Ce:ZnO Nanoleaf (NL) Growth (Hydrothermal Method):
- Precursor Solution: 0.2 M zinc acetate dihydrate (Zn(CH₃COO)₂ · 2H₂O), 11 mM cerium nitrate hexahydrate (Ce(NO₃)₂ · 6H₂O), and 3 mM hexamethylenetetramine (CH₂)₆N₄) in anhydrous ethanol.
- pH Adjustment: Sodium hydroxide (NaOH) was added to adjust the precursor solution pH to 10.
- Reaction Conditions: The solution was treated in an autoclave at 150 °C for 24 hours.
Post-Processing: Samples were rinsed repeatedly with absolute ethanol and dried at Room Temperature (RT).
Device Contacting: Ohmic contacts were established using Ag/ITO/Ag and Ag/BDD/Ag configurations for electrical testing.

6CCVD Solutions & Capabilities

The successful replication and extension of this high-temperature optoelectronic research depend entirely on access to high-quality, customizable Boron-Doped Diamond (BDD) substrates. 6CCVD is uniquely positioned to supply the necessary materials and engineering services.

Applicable Materials

To replicate or advance the n-Ce:ZnO NL/p-BDD heterojunction, researchers require high-quality p-type diamond films.

6CCVD Material Recommendation	Description & Relevance to Research
Heavy Boron Doped PCD	Ideal for the p-type semiconductor layer. 6CCVD offers high-quality Polycrystalline Diamond (PCD) films with controlled boron doping levels (up to 10²¹ cm^-3) necessary to achieve the required carrier concentration (1.46 x 10¹⁸ cm^-3) and low resistivity (1.09 x 10^-1 Ω cm).
Optical Grade SCD/PCD	For applications requiring superior light extraction or transmission in the UV/blue spectrum (365 nm), 6CCVD provides optical-grade diamond with low defect density and high transparency.
Custom Diamond Substrates	The paper used a 4 µm film. 6CCVD can supply BDD films in thicknesses ranging from 0.1 µm up to 500 µm (PCD/SCD) or up to 10 mm for robust substrates, allowing for optimization of thermal management and device rigidity.

Customization Potential

The research utilized specific dimensions and contact materials. 6CCVD offers comprehensive customization to meet precise experimental needs:

Custom Dimensions: While the paper’s dimensions were not specified, 6CCVD provides BDD plates and wafers up to 125 mm in diameter (PCD), enabling scale-up and integration into standard semiconductor processing lines.
Precision Thickness Control: We offer precise control over BDD film thickness, crucial for optimizing the depletion region width and tunneling characteristics investigated in this study.
Advanced Metalization Services: The paper used Ag/ITO contacts. 6CCVD offers in-house deposition of standard and custom metal stacks (including Ti, Pt, Au, Pd, W, and Cu), allowing researchers to optimize ohmic contacts and thermal dissipation for high-temperature operation (up to 175 °C and beyond).
Surface Finish: For optimal subsequent layer growth (like the ZnO NLs), 6CCVD provides ultra-smooth polishing services, achieving Ra < 1 nm for SCD and Ra < 5 nm for inch-size PCD, ensuring high-quality interface formation.

Engineering Support

The successful integration of Ce:ZnO NLs with BDD requires deep understanding of interface physics, defect engineering, and high-temperature transport mechanisms.

6CCVD’s in-house PhD engineering team specializes in diamond material science and can assist researchers with:

Material Selection: Determining the optimal doping concentration and crystal structure (SCD vs. PCD) of BDD to match the required electrical properties (e.g., Fermi level alignment) for doped metal oxide/diamond heterojunctions.
Interface Optimization: Consulting on surface preparation and metalization schemes to ensure reliable, low-resistance ohmic contacts for high-temperature optoelectronic devices.
Global Logistics: Ensuring reliable, fast global shipping (DDU default, DDP available) of sensitive diamond materials directly to your lab.

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.

View Original Abstract

The n-type Ce:ZnO (NL) grown using a hydrothermal method was deposited on a p-type boron-doped nanoleaf diamond (BDD) film to fabricate an n-Ce:ZnO NL/p-BDD heterojunction. It shows a significant enhancement in photoluminescence (PL) intensity and a more pronounced blue shift of the UV emission peak (from 385 nm to 365 nm) compared with the undoped heterojunction (n-ZnO/p-BDD). The prepared heterojunction devices demonstrate good thermal stability and excellent rectification characteristics at different temperatures. As the temperature increases, the turn-on voltage and ideal factor (n) of the device gradually decrease. The electronic transport behaviors depending on temperature of the heterojunction at different bias voltages are discussed using an equilibrium band diagram and semiconductor theoretical model.

Tech Support

Original Source

DOI: https://doi.org/10.3390/nano12213773

References

2006 - Quasi-one-dimensional metal oxide materials—Synthesis, properties and applications [Crossref]
2018 - Structural, optical and electrical properties of a Schottky diode fabricated on Ce doped ZnO nanorods grown using a two step chemical bath deposition [Crossref]
2002 - Nanowire Ultraviolet Photodetectors and Optical Switches [Crossref]
1994 - ZnO-thin film chemical sensors
1994 - Growth of ZnO films on GaAs substrates with a SiO2 buffer layer by RF planar magnetron sputtering for surface acoustic wave applications [Crossref]
2021 - High performance NiO/Ag/NiO transparent conducting electrodes for p-Si/n-ZnO heterojunction photodiodes [Crossref]
2015 - n-ZnO/p-4H-SiC diode: Structural, electrical, and photoresponse characteristics [Crossref]
2020 - Enhanced Piezoresistive Behavior of SiC Nanowire by Coupling with Piezoelectric Effect [Crossref]
2021 - Preparation and photoelectrochemical properties of hierarchical heterostructure ZnO/CuO array [Crossref]