A cross-coupled tunnel diode (XTD) device with large peak-to-valley current ratio (PVCR) is disclosed. A memory cell circuit comprising XTD devices is also disclosed. The XTD device includes an N-type semiconductor coupled to a P-type semiconductor. A first gate is disposed on the N-type semiconductor and a second gate is disposed on the P-type semiconductor. The first gate is coupled to the output terminal, which is further coupled to the P-type semiconductor. The second gate is coupled to the input terminal, which is coupled to the N-type semiconductor. As reverse bias voltage increases, band-to-band tunneling from valence band to conduction band initially generates increasing current, but the rising bias voltage closes the band to band tunneling window, creating a gated negative differential resistance behavior. The current drops off as the bias voltage further increases. In some examples, a ratio of peak-to-valley current ratio may exceed 103 or 105.