Design and Analysis of Gallium Nitride-Based p-i-n Diode Structure for Betavoltaic Cell with Enhanced Output Power Density.

Young Jun Yoon,Jae Sang Lee,In Man Kang,Dong Seok Kim,Jung Hee Lee

doi:10.3390/mi11121100

Young Jun Yoon, Jae Sang Lee + Show 3 more

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https://doi.org/10.3390/mi11121100

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Abstract

In this work, Gallium Nitride (GaN)-based p-i-n diodes were designed using a computer aided design (TCAD) simulator for realizing a betavoltaic (BV) cell with a high output power density (Pout). The short-circuit current density (JSC) and open-circuit voltage (VOC) of the 17 keV electron-beam (e-beam)-irradiated diode were evaluated with the variations of design parameters, such as the height and doping concentration of the intrinsic GaN region (Hi-GaN and Di-GaN), which influenced the depletion width in the i-GaN region. A high Hi-GaN and a low Di-GaN improved the Pout because of the enhancement of absorption and conversion efficiency. The device with the Hi-GaN of 700 nm and Di-GaN of 1 × 1016 cm−3 exhibited the highest Pout. In addition, the effects of native defects in the GaN material on the performances were investigated. While the reverse current characteristics were mainly unaffected by donor-like trap states like N vacancies, the Ga vacancies-induced acceptor-like traps significantly decreased the JSC and VOC due to an increase in recombination rate. As a result, the device with a high acceptor-like trap density dramatically degenerated the Pout. Therefore, growth of the high quality i-GaN with low acceptor-like traps is important for an enhanced Pout in BV cell.

Highlights

Betavoltaic (BV) cells using a radioisotope have been developed for micro-battery applications, such as a power source of bio-medical implants and extreme environmental sensors [1,2,3], because of their long lifetime and micro-size. 63 Ni radioisotope–based BV cells can be used for a long period due to a half-life of about 100 years
The p-i-n diode between p-type Gallium Nitride (GaN) (p-GaN) and n-type GaN (n-GaN) regions to obtain a wide width in the structure is the conventional diode structure, which consisted of an intrinsic GaN (i-GaN) region depletion region
The doping concentration of i-GaN (Di-GaN) determines the depletion width, which affects the conversion efficiency between p-type GaN (p-GaN) and n-type GaN (n-GaN) regions to obtain a wide width in the depletion for BV cells

Summary

Introduction

Betavoltaic (BV) cells using a radioisotope have been developed for micro-battery applications, such as a power source of bio-medical implants and extreme environmental sensors [1,2,3], because of their long lifetime and micro-size. 63 Ni radioisotope–based BV cells can be used for a long period due to a half-life of about 100 years. The BV cells based on various semiconductors such as Si [4,5], GaAs [6], SiC [7,8,9], GaN [10,11,12,13,14], and GaP [15] have been studied for high power conversion efficiency. It is known that GaN-based BV cells can theoretically obtain superior conversion efficiency because of a wider energy bandgap. GaN-based BV cells are more suitable for BV applications with long-term stability because GaN material has exhibited a strong radiation hardness [16,17], which can reduce the effects of radiation damage on device performances [18]. Many researchers have made progress in the optimization design of diode structures using

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