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Topological semimetals (TSMs), a class of gapless electronic phases exhibiting topologically stable crossings of bulk energy bands, have attracted tremendous interest in the condensed matter physics community recently. Based on the origin of the band crossing, TSMs can be classified into Dirac semimetals (DSMs), Weyl semimetals (WSMs) and others. Recently, the transition metal dichalcogenide ZrTe₂ has been theoretically predicted and experimentally demonstrated to possess a DSM phase. We used molecular beam epitaxy to synthesize ZrTe₂ thin films on insulating sapphire (0001) substrates and performed systematic in vacuo angle-resolved photoemission spectroscopy (ARPES) measurements. The observation of the Dirac cone in the ARPES spectra of ZrTe₂ thin films confirms the DSM phase. We also measured the temperature dependence of the ex-situ magneto-transport and found that negative magnetoresistance is absent in our films. We are also exploring the quantum phase transition from DSM to WSM by transition metal doping into these ZrTe₂ films.