GaN tunnel junction as a current aperture in a blue surface-emitting light-emitting diode

Abstract

We have demonstrated surface-emitting GaN-based diodes with a buried tunnel junction (TJ) current aperture. The current confinement aperture for lateral injection current was defined by mesa etch of a TJ structure and regrowth of current blocking layer surrounding the TJ mesa. Lateral electron current drives a tunnel contact junction providing hole injection into the active region. The very uniform light emission just through a buried TJ aperture represents that the buried TJ structure acts very effectively as a confinement aperture of lateral current injection, particularly in GaN-based vertical-cavity surface-emitting lasers.

Highly reliable nitride-based LEDs with SPS+ITO upper contacts

“…Details of the MOCVD growth procedures have already been published elsewhere [9]- [13]. Briefly, the LED structure consists a 30-nm-thick low-temperature GaN nucleation layer, a 2-m-thick Si-doped n-GaN buffer layer, an InGaN-GaN MQW active region, a 50-nm-thick Mg-doped p Al Ga N cladding layer, a 0.25-m-thick Mg-doped p-GaN layer and an Si-doped n -SPS tunnel contact structure [14]. The undoped InGaN-GaN MQW active region consists 5 periods of 3 nm-thick In Ga N well layers and 7-nm-thick GaN barrier layers.…”

Micro-light-emitting diodes with III–nitride tunnel junction contacts grown by metalorganic chemical vapor deposition

“…10) GaN TJs grown by metalorganic chemical vapor deposition (MOCVD) have been explored since 2001 but have faced issues of large voltage penalties of 1.0 to 3.2 V and low light output power. [11][12][13] One problem with MOCVD-grown TJs is the magnesium memory effect. 14) Excess magnesium lingering in the reactor may diffuse into n-GaN layers and compensate for silicon, reducing the concentration of donors available.…”

Ultralow-voltage-drop GaN/InGaN/GaN tunnel junctions with 12% indium content

“…Initial studies on TJ contacts with p-GaN were reported by several research groups. [1][2][3][4][5] However, the interband tunneling process was inefficient, and the devices showed a high turn-on voltage and on-resistance, precluding wide-spread adoption of TJs in optoelectronic devices. After low-resistance polarization-engineered n-GaN=InGaN= p-GaN junctions grown by plasma-assisted molecular beam epitaxy (PA-MBE) were demonstrated, efforts to utilize polarization-assisted high electric fields to enhance the tunneling process by reducing the tunneling width and barrier for the carriers rekindled interest in wide-band-gap TJs.…”