| CPC H01L 31/105 (2013.01) [H01L 31/03046 (2013.01)] | 24 Claims |

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1. A PIN-type photodiode comprising:
a p-type contact;
an n-type contact;
a first absorbing layer characterized by a first absorption coefficient; and
a second absorbing layer characterized by a second absorption coefficient, wherein the second absorption coefficient is greater than the first absorption coefficient,
wherein the first absorbing layer is disposed between the p-type contact and the second absorbing layer,
wherein the second absorbing layer is disposed between the first absorbing layer and a non-absorbing accelerating layer, wherein the non-absorbing accelerating layer is disposed between the second absorbing layer and a non-absorbing drift layer, the non-absorbing accelerating layer configured to cause an increase in drift speed of photoinduced electrons freed by absorption of light by the first absorbing layer and/or the second absorbing layer, and
wherein the non-absorbing drift layer is disposed between the non-absorbing accelerating layer and the n-type contact, wherein the non-absorbing drift layer is a carrier transport layer having a third absorption coefficient, wherein the third absorption coefficient is less than the first absorption coefficient and the second absorption coefficient, wherein the non-absorbing drift layer is configured such that an electric field in the non-absorbing drift layer is lower than an electric field in the first absorbing layer and the second absorbing layer,
wherein a thickness of the second absorbing layer has an upper boundary defined by a strain relaxation of a crystal lattice constant of the first absorbing layer.
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