Efficient Free-Exciton Recombination Emission from Diamond Diode at Room Temperature

Abstract

Free-exciton recombination emission of 235 nm in wavelength is obtained by current injection at room temperature from a diamond-based pn junction diode composed of B-doped crystal grown by high-temperature, high-pressure synthesis and a S-doped homoepitaxial layer grown by the chemical vapor deposition method. The diode shows a clear rectification characteristic and a high external quantum efficiency of excitonic emission, 8×10-5, which indicates that the excitonic emission of diamond is a good candidate for application to semiconductor UV-light-emitting devices. A defect-induced light emission and large leakage current indicate that a higher UV emission efficiency is expected with improvement of the junction quality.

Images and Energy Distributions of Electrons Emitted from a Diamond pn-Junction Diode

“…Realization of deepultraviolet emitting pn-junction diamond diodes has been reported in the last decade [1,2]. The realization of pn-junction diamond diodes opened the door for durable high-current electron sources.…”

Photonic Devices

“…Horiuchi et al (Tokyo Gas group) developed the research and development of a diamond-based LED in a new positive direction [114]. They synthesized a B-doped p-type layer by homoepitaxial CVD growth on a low-resistance B-doped HPHT (100) substrate and further synthesized an S-doped n-type layer to make diamond p-n junction LEDs.…”

“…114 shows reports of the maximum external efficiencies of group-III nitride LEDs at the peak emission wavelengths up to August 2005.…”

Excitonic emission and N‐ and B‐incorporation in homoepitaxial CVD‐grown diamond investigated by cathodoluminescence

“…Despite early announcements [1], the considerable difficulty of achieving suitable and controlled n-type conduction in this material has hindered the practical production of bipolar diamond devices, and most applications under development are using either a Schottky diode design or a field effect transistor configuration. Nevertheless, the remarkable progress in n-type doping of diamond [2][3][4] that has been observed since 1997 in various laboratories has led to a few reports of p/n junctions [5][6][7][8] with rectification ratios between 10 3 [5] and 10 5 [6,7]. Under high forward bias, these devices have been shown to emit excitonic electroluminescence in the UV.…”

“…Under high forward bias, these devices have been shown to emit excitonic electroluminescence in the UV. However, luminescence is shown to be dominated by a defect-related visible range emission [6][7][8] in such devices. Most of the defect-related visible luminescence involves nitrogen and/or boron incorporated to the lattice in different forms.…”