Heterojunction diodes are fabricated using p-type Ge2Sb2Te5 and low doped n-type silicon wafer. Rectification is observed with a ratio of forward-to-reverse current as high as 104 and 103 for crystal-Ge2Sb2Te5/n-Si junction and amorphous-Ge2Sb2Te5/n-Si junction, respectively. The approximate equilibrium energy-band diagrams for both crystal-Ge2Sb2Te5/n-Si heterojunction diodes and amorphous-Ge2Sb2Te5/n-Si heterojunction diodes are proposed to explain the properties of the p-Ge2Sb2Te5/n-Si heterojunction diode. Properties of a p-n heterojunction diode based on Ge2Sb2Te5 are proposed to apply in 0T1R cross-point structure array for reliable read operation and for decreasing the sneaking current.

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