Ir photodetector with graphene and phase change layers and related methods

An infrared (IR) photodetector comprising:

• an electrically conductive layer comprising at least one of gold, silver, and platinum;
• a first dielectric layer over the electrically conductive layer;
• a phase change material layer over the first dielectric layer and having a thickness gradient with different phase transition temperatures;
• first and second electrically conductive contacts coupled to the phase change material layer, the phase change material layer having a first height value adjacent to the first electrically conductive contact, and a second height value adjacent to the second electrically conductive contact, the second height value being different than the first height value;
• a graphene layer over the phase change material layer and having a perforated pattern therein;
• and
• circuitry configured to
• apply a pulse train bias voltage between the first and second electrically conductive contacts, and
• detect a sensing current in the phase change material layer caused by IR radiation received by the graphene layer, the IR radiation having a frequency range based upon the pulse train bias voltage.

A method of making an infrared (IR) photodetector, the method comprising:

• forming a first dielectric layer over an electrically conductive layer;
• forming a phase change material layer over the first dielectric layer, the phase change material layer having a thickness gradient with different phase transition temperatures;
• forming first and second electrically conductive contacts coupled to the phase change material layer, the phase change material layer having a first height value adjacent to the first electrically conductive contact, and a second height value adjacent to the second electrically conductive contact, the second height value being different than the first height value;
• forming a graphene layer over the phase change material layer and having a perforated pattern therein;
• and
• coupling circuitry to
• apply a bias voltage between the first and second electrically conductive contacts, and
• detect a sensing current in the phase change material layer caused by IR radiation received by the graphene layer, the IR radiation having a frequency range based upon the bias voltage.