Evidence of minority carrier injection efficiency >90% in an epitaxial graphene/SiC Schottky emitter bipolar junction phototransistor for ultraviolet detection
Abstract
In this letter, we report the UV detection characteristics of an epitaxial graphene (EG)/SiC based Schottky emitter bipolar phototransistor (SEPT) with EG on top as the transparent Schottky emitter layer. Under 0.43 μW UV illumination, the device showed a maximum common emitter current gain of 113, when operated in the Schottky emitter mode. We argue that avalanche gain and photoconductive gain can be excluded, indicating minority carrier injection efficiency, γ, as high as 99% at the EG/p-SiC Schottky junction. This high γ is attributed to the large, highly asymmetric barrier, which EG forms with the p-SiC. The maximum responsivity of the UV phototransistor is estimated to be 7.1 A/W. The observed decrease in gain with increase in UV power is attributed to recombination in the base region, which reduces the minority carrier lifetime.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jan 25, 2016
- Source ID
- 10.1063/1.4940385
Entities
People
- Gabriel D Brown
- J. Andrews
- M. V. S. Chandrashekhar
- Sabih U. Omar
- Shamaita S. Shetu
- T. S. Sudarshan
- Venkata S. N. Chava
Organizations
- National Science Foundation
- Office of Naval Research
- United States Department of Energy
- University of South Carolina