Novel Si1−xGex/Si heterojunction internal photoemission long-wavelength infrared detectors
- 1 October 1990
- journal article
- research article
- Published by AIP Publishing in Applied Physics Letters
- Vol. 57 (14) , 1422-1424
- https://doi.org/10.1063/1.103454
Abstract
A new approach to the design of a Si‐based infrared detector is demonstrated, based on internal photoemission over a Si1−x Ge x /Si heterojunction barrier. The heterojunction internal photoemissiondevice structure is grown by molecular beam epitaxy(MBE). The detector requires a degenerately dopedp +‐Si1−x Ge x layer for strong infrared absorption and photoresponse. Doping concentrations to 1020 cm−3 are achieved using boron from a HBO2 source during MBEgrowth of the Si1−x Ge x layers. The photoresponse of this device is tailorable, and most significantly, can be extended into the long‐wavelength infrared regime by varying the Ge ratio x in the Si1−x Ge x layers. Results are obtained with x=0.2, 0.28, 0.3, and 0.4 on patterned Si (100) substrates. Photoresponse at wavelengths ranging from 2 to 10 μm is obtained with quantum efficiencies above ∼1% in these nonoptimized structures.Keywords
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