Artistic
illustration of GaSe-graphene device.
(February 20, 2016) The
2D material device designed and fabricated by Aalto University's researchers
may prove useful in wearable electronics and sensors.
Graphene has been predicted to revolutionise electronics
since Andre Geim and Konstantin Novoselov received the Nobel Prize in physics
in 2010 for the breakthrough experiments conducted with the material.
Graphene is a so-called 2D material, that is, it is only one
atom thick film. Graphite, which is a well-known material, consists of huge
number of graphene layers on top of each other. Despite being ultimately thin,
graphene is an excellent conductor of electricity and heat, and it is extremely
durable. However, its band gap is zero, which limits its application in some
semiconductor applications as it results in low intrinsic on/off ratio. Now
Aalto University's researchers have managed to fabricate an
electricity-conducting material combination with especially promising
properties by merging graphene and another 2D material, gallium selenide. In the
semiconductor industry this kind of structure is known as a heterojunction. The
results were recently published in the Advanced Materials science journal.
'This is the first time when gallium selenide is used with
graphene. This kind of new heterojunctions will be important in future as
conventional heterojunctions are already vital part of current semiconductor
industry forming the basis for example for lasers and transistors.', explains
Juha Riikonen, head of the research group.
'Because the component is made of 2D materials, it is, in
comparison with those containing silicon, extremely thin, approximately one
ten-thousandth part of the diameter of a single hair', post-doctoral researcher
Wonjae Kim explains.
From research labs to
industry
In earlier research, the 2D structures combined with
graphene were fabricated manually, layer by layer, which made the process slow,
challenging and difficult to scale. The component structure developed by
Riikonen, Kim and their colleagues utilized elements from both lateral and
vertical device design enabling the use of standard fabrication methods
utilized in the semiconductor industry instead of laborious manual fabrication.