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Title: Low temperature p-type doping of (Al)GaN layers using ammonia molecular beam epitaxy for InGaN laser diodes

We demonstrate state-of-the-art p-type (Al)GaN layers deposited at low temperature (740 °C) by ammonia molecular beam epitaxy (NH{sub 3}-MBE) to be used as top cladding of laser diodes (LDs) with the aim of further reducing the thermal budget on the InGaN quantum well active region. Typical p-type GaN resistivities and contact resistances are 0.4 Ω cm and 5 × 10{sup −4} Ω cm{sup 2}, respectively. As a test bed, we fabricated a hybrid laser structure emitting at 400 nm combining n-type AlGaN cladding and InGaN active region grown by metal-organic vapor phase epitaxy, with the p-doped waveguide and cladding layers grown by NH{sub 3}-MBE. Single-mode ridge-waveguide LD exhibits a threshold voltage as low as 4.3 V for an 800 × 2 μm{sup 2} ridge dimension and a threshold current density of ∼5 kA cm{sup −2} in continuous wave operation. The series resistance of the device is 6 Ω and the resistivity is 1.5 Ω cm, confirming thereby the excellent electrical properties of p-type Al{sub 0.06}Ga{sub 0.94}N:Mg despite the low growth temperature.
Authors:
; ; ;  [1] ; ;  [2] ; ; ; ;  [3]
  1. ICMP, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland)
  2. NOVAGAN AG, CH-1015 Lausanne (Switzerland)
  3. EXALOS AG, CH-8952 Schlieren (Switzerland)
Publication Date:
OSTI Identifier:
22395514
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 24; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALUMINIUM COMPOUNDS; AMMONIA; CLADDING; DOPED MATERIALS; ELECTRIC CONDUCTIVITY; ELECTRIC POTENTIAL; GALLIUM NITRIDES; LASERS; LAYERS; MOLECULAR BEAM EPITAXY; ORGANOMETALLIC COMPOUNDS; P-TYPE CONDUCTORS; QUANTUM WELLS; TEMPERATURE DEPENDENCE; THRESHOLD CURRENT; VAPOR PHASE EPITAXY; WAVEGUIDES